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fifteen or twenty minutes, exert an influence which is great enough to very materially influence the discharge of water into wells, field drains, springs and river channels. It is well known too, in the case of breathing or blowing wells, that there is for days .together a continuous flow of air out of and into the ground, the currents being strong enough, in a case which we have personally observed, to rattle loose two-inch planks lying over the well, itself nearly a hundred feet deep and four feet in diameter. In this particular case we were called to examine the well because it was impossible to prevent the suction pipe in the well freezing and bursting during the winter, caused by the large volume of cold air sinking into the well at times of high pressure when the thermometer was very low. The owner informed me that in digging the well, after a depth of eighty feet had been reached, work was stopped for the Christmas holidays and that after taking up the work again the gravel was found frozen so that a pick was necessary to loosen it before beginning digging.

We have observed fluctuations in the discharge of water from tile drains, associated with and apparently caused by changes of barometric pressure, amounting to fifteen per cent., and in the case of a deep well, discharg. ing through a six-inch pipe, where the rate of flow was measured in a reservoir on ten consecutive days, the discharge per minute was found to vary between the wide limits of 15.441 and 13.947 cubic feet per minute,-a variation of fully ten per cent. We have also secured autographic records on the Wisconsin and Fox Rivers and from Lake Mendota which seem to indicate that the general seepage over wide areas changes its rate with changes in barometric pressure to such an extent that when the discharge is collected into channels the differences in depth are measurable, and when we have such changes as these it is difficult to believe that the inflow and outflow of air are not greater than is suggested by the conclusions of this Bulletin.

In regard to the influence of simple diffusion, in effecting soil aeration, it appears to the writer that the author has obtained values

which must be much too large for field conditions. In carefully measuring the rates of diffusion, under the conditions of rigid control, which he did, the author has done exactly the right thing; but what is lacking is supporting field checks which are greatly needed in verifying the conclusions reached, particularly when the results are used so precisely as to compute the amount of carbonic acid escaping from a given field surface from the per cent. of carbonic acid found in the soil air at a given distance below the surface, where the porosity of the soil is known. Referring specifically to some of the author's data: If it is true, as indicated on page 39, that carbonic acid was escaping from soil in the flower bed in front of the building of the Bureau of Soils at the time of observation at the rate of .04 of a cubic foot per day and that it was being produced at this rate in the soil below the depth of six inches throughout the growing season-let us assume of 120 days— this would mean a production of carbonic acid, through the oxidizing of organic matter, at the rate of 209,088 cubic feet per acre; and, taking the weight of a cubic foot of carbonic acid at .12323 pounds, there would have been a loss from the soil of 7,026 pounds of carbon per acre. This amount of carbon represents, using an analysis of Hall's, 13,970 pounds of water-free grass per acre, or eight tons of hay containing the usual 15 per cent of moisture. If we take Ebermayer's observations on the amount of carbonic acid in soil air, extending over a full year, except that August, September and October are not included, as given in the Bulletin, we shall find by the method of the author a still larger loss of carbonic acid. We use for this computation the mean amounts found for the year under the five conditions reported upon. At a depth of 15 centimeters (5.9 inches) the mean amount of carbonic acid found in the soil air was 1.09 per cent., the smallest amount in any single observation being .02 per cent., the next smaller .13 per cent. and the next .27 per cent., while the highest amount found was 4.61 per cent. Taking 120 days, as in the former case, and calculating from the table the amount of carbon carried out of the soil during this period, expressing it again as dry grass on the basis of Hall's analysis, the amount required would be 27,420 pounds per acre or, expressed as hay containing 15 per cent. water, 15.7 tons. Again, using Ebermayer's determinations for the depth of 70 centimeters (27.6 inches) and 120 days, the computed loss of carbonic acid from the soil below this depth would be represented by that carried by 31,960 pounds of dry grass or 17.3 tons of hay per acre. In speaking of the first instance cited the author says: “We may say, then, that, in this case, carbonic acid is escaping from the soil at the rate of about 0.04 cubic foot per day per square foot and therefore that this was the rate of production of carbonic acid in the soil at this place below the depth of six inches.” The amount of carbon thus carried out of the soil, according to the assumption and calculation, would be greater than the amount we have calculated above by whatever was produced in the surface six inches. It is clear, however, that no such losses of carbonic acid, resulting from the decomposition of organic matter, could be maintained year after year, as the amount of organic matter in the root system of a crop is not equal to that produced above ground, at least usually, and the amounts produced above ground are only rarely equal to the amounts computed; indeed they are seldom more than one third of those quantities. It must be concluded, therefore, that the laboratory observations and methods of computation give a rate of diffusion of carbonic acid from the soil of a field much greater than actually occurs as a seasonal average. It should be noted that in getting these enormous losses of carbonic acid from the soil we have included only one third of the year, while Ebermayer's observations show that the amounts present in the soil at all seasons, including even winter, are large.

In view of the relations to which we have called attention it is clear that the generalizations cited require critical field trials to be made, bringing them to suitable tests before they should be accepted with full confidence

F. H. King. Madison, Wis.,

September 16, 1905.

THE QUESTION AS TO WHETHER FALCONS WHEN SOARING INTERLOCK THEIR PRIMARY WING

FEATHERS. The observations of Mr. Trowbridge upon the habit of hawks when soaring to overlap their primaries (i. e., on the upper side of the wing) have several times been commented upon adversely. And a well-known ornithologist has objected that this behavior of feathers has not been previously observed, in spite of the voluminous field notes as to the habits of hawks, and that no one has been able to confirm the observation of interlocking feathers. Accordingly, I am led to jot down the following notes in favor of Mr. Trowbridge's results, —for my observations are at first hand and were made, I believe, under quite favorable conditions.

It so happened that we were coming up the narrow canal from Sakai to Matsue in the face of a strong wind, so strong, indeed, that our small steamer labored to make headway against it. At one point we disturbed a kite, Milvus melanotus-a very common bird, by the way, along Japanese waterways—which rose slowly in the face of the wind and after making several circles followed the margin of the canal, flying and soaring, almost opposite the boat and making about equal headway. It did not occur to me at the moment that the opportunity was a favorable one for watching the wing feathers (for the bird was sometimes as near as a hundred feet), when my eye was caught by the behavior of the primaries. The hawk was flying low, about the height of the eye, and when the wing passed through the plane of the horizon I could see as the wing flapped that several primaries stood out sharply, finger-like, dorsal to the plane of the descending wing. This was so conspicuous, indeed, that it seemed difficult to conclude that these feathers could fold under one another when, in face of a strong wind, the wings became passive in soaring. Nevertheless, the distance of the bird was so great that I could not convince myself that the interlocking actually took place; I was only sure that the primaries were bowed, so that in soaring this part of the wing must have been greatly strengthened by the closely opposed feathers. For several minutes the hawk thus flew alongside of the boat, with quite regular periods of flapping and soaring; then, suddenly shifting its course, it circled out, soaring, passing over my head at a distance of about twenty feet. I could then see plainly that the primaries of one wing (right) were interlocked--the condition of the other wing I had not time to observe.

My conclusion, therefore, is that the interlocking of the primaries of hawks takes place, as Mr. Trowbridge has shown, under the conditions of soaring in the face of a strong wind.

BASHFORD DEAN. RINKAI JIKENJO, MISAKI-MIU'RA, JAPAN,

September 3, 1903.

SPECIAL ARTICLES. THE CHROMOSOMES IN: RELATION TO THE DETER

MINATION OF SEX IN INSECTS. MATERIAL procured during the past summer demonstrates with great clearness that the sexes of Hemiptera show constant and characteristic differences in the chromosome groups, which are of such a nature as to leave no doubt that a definite connection of some kind between the chromosomes and the determination of sex exists in these animals. These differences are of two types. In one of these, the cells of the female possess one more chromosome than those of the male; in the other, both sexes possess the same number of chromosomes, but one of the chromosomes in the male is much smaller than the corresponding one in the female (which is in agreement with the observations of Stevens on the beetle Tenebrio). These types may conveniently be designated as A and B. respectively. The essential facts have been determined in three genera of each type, namely, (type A) Protenor belfragei, Anasa tristis and Alydus pilosulus, and (type B) Lygaus turcicus, Euschistus fissilis and Conus delius. The chromosome groups have been examined in the dividing oogonia and ovarian follicle cells of the female and in the dividing spermatogonia and investing cells of the testis in case of the male.

Type A includes those forms in which (as

has been known since Henking's paper of 1890 on Pyrrochoris) the spermatozoa are of two clàsses, one of which contains one more chromosome (the so-called “accessory' or heterotropic chromosome) than the other. In this type the somatic number of chromosomes in the female is an even one, while the somatic number in the male is one less (hence an odd number) the actual numbers being in Protenor and Alydus $ 14, ở 13, and in Anasa $ 22,

21. A study of the chromosome groups in the two sexes brings out the following additional facts. In the cells of the female all the chromosomes may be arranged two by two to form pairs, each consisting of two chromosomes of equal size, as is most obvious in the beautiful chromosome groups of Protenor, where the size differences of the chromosomes are very marked. In the male all the chromosomes may be thus symmetrically paired with the exception of one which is without a mate. This chromosome is the accessory' or heterotropic one; and it is a consequence of its unpaired character that it passes into only one half of the spermatozoa.

In type B all of the spermatozoa contain the same number of chromosomes (half the somatic number in both sexes), but they are, nevertheless, of two classes, one of which contains a large and one a small 'idiochromosome.' Both sexes have the same somatic . number of chromosomes (fourteen in the three examples mentioned above), but differ as follows: In the cells of the female (oogonia and follicle-cells) all of the chromosomes may, as in type A, be arranged two by two in equal pairs, and a small idiochromosome is not present. In the cells of the male all but two may be thus equally paired. These two are the unequal idiochromosomes, and during the maturation process they are so distributed that the small one passes into one half of the spermatozoa, the large one into the other half.

These facts admit, I believe, of but one interpretation. Since all of the chromosomes in the female (oogonia) may be symmetrically paired, there can be no doubt that synapsis in this sex gives rise to the reduced number of symmetrical bivalents, and that consequently

all of the eggs receive the same number of chromosomes. This number (eleven in Anasa, seven in Protenor or Alydus) is the same as that present in those spermatozoa that contain the “accessory' chromosome. It is evident that both forms of spermatozoa arę functional, and that in type A females are produced from eggs fertilized by spermatozoa that contain the 'accessory' chromosome, while males are produced from eggs fertilized by spermatozoa that lack this chromosome (the reverse of the conjecture made by McClung). Thus if n be the somatic number in the female n/2 is the number in all of the matured eggs, n/2 the number in one half of the spermatozoa (namely, those that contain the 'accessory'), and n/2—1 the number in the other half. Accordingly: In fertilization

Eyg + spermatozoon =n (female).

Egy + spermatozoon », —1=n-1 (male). The validity of this interpretation is completely established by the case of Protenor, where, as was first shown by Montgomery, the

accessory' is at every period unmistakably recognizable by its great size. The spermatogonial divisions invariably show but one such large chromosome, while an equal pair of exactly similar chromosomes appear in the oogonial divisions. One of these in the female must have been derived in fertilization from the egg-nucleus, the other (obviously the “ accessory ') from the sperm-nucleus. It is evident, therefore, that all of the matured eggs must before fertilization contain a chromosome that is the maternal mate of the 'accessory' of the male, and that females are produced from eggs fertilized by spermatozoa that contain a similar group (i. e., those containing the accessory '). The presence of but one large chromosome (the 'accessory') in the somatic nuclei of the male can only mean that males arise from eggs fertilized by sper matozoa that lack such a chromosome, and that the single 'accessory' of the male is derived in fertilization from the egg nucleus.

In type B all of the eggs must contain a chromosome corresponding to the large idio

chromosome of the male. Upon fertilization by a spermatozoon containing the large idiochromosome a female is produced, while fertilization by a spermatozoon containing the small one produces a male.

The two types distinguished above may readily be reduced to one; for if the small idiochromosome of type B be supposed to disappear, the phenomena become identical with those in type A. There can be little doubt that such has been the actual origin of the latter type, and that the accessory' chromosome was originally a large idiochromosome, its smaller mate having vanished. The unpaired character of the accessory' chromosome thus finds a complete explanation, and its behavior loses its apparently anomalous character.

The foregoing facts irresistibly lead to the conclusion that a causal connection of some kind exists between the chromosomes and the determination of sex; and at first thought they naturally suggest the conclusion that the idiochromosomes and heterotropic chromosomes are actually sex determinants, as was conjectured by McClung in case of the 'accessory' chromosome. Analysis will show, however, that great, if not insuperable, difficulties are encountered by any form of the assumption that these chromosomes are specifically male or female sex determinants. It is more probable, for reasons that will be set forth hereafter, that the difference between eggs and spermatozoa is primarily due to differences of degree or intensity, rather than of kind, in the activity of the chromosome groups in the two sexes; and we may here find a clue to a general theory of sex determination that will accord with the facts observed in hemiptera. A significant fact that bears on this question is that in both types the two sexes differ in respect to the behavior of the idiochromosomes or accessory' chromosomes during the synaptic and growth periods, these chromosomes assuming in the male the form of condensed chromosome nucleoli, while in the female they remain, like the other chromosomes, in a diffused condition. This indicates that during these periods these chromosomes play a more active part in the metabolism of the cell in the female than in the male. The primary factor in the differentiation of the germ cells may, therefore, be a matter of metabolism, perhaps one of growth.

EDMUND B. Wilson. ZOOLOGICAL LABORATORY, COLUMBIA UNIVERSITY,

October 3, 1905.

Of the various theories which might be advanced in order to explain this distribution it seems most reasonable at present to select the one which presupposes a comparatively late immigration of this genus from southeastern Asia into Europe after a late Miocene land connection had been established a theory which would account for the failure of these toads to reach Spain on the one side and Japan on the other.

The supposed original central form in southeastern Asia has now been found, and the theory to a great extent verified almost at the very moment of its publication.

LEONHARD STEJNEGER. U. S. NATIONAL MUSEUM, WASHINGTON, D. C.,

August 31, 1905.

THE GEOGRAPHICAL DISTRIBUTION OF THE

BELL-TOADS. At the meeting of the Association of American Geographers in Philadelphia, December 29, 1904, I read a paper on the 'Geographical Distribution of the Discoglossoid Toads in the Light of Ancient Land Connections,' in which I made the following statement:

All indications point towards the country southeast of the Himalayas as the original center of the radiation of the discoglossoid toads, as well as of their near relations the pelodytoid toads. The former are not now found in this region; but that fact weighs but little in view of Ascaphus having remained unknown on this continent till 1899, and thus far known only from a single speci. men.

This statement assumes almost the character of a prophesy in view of the fact that Dr. G. A. Boulenger, a month later, announced the discovery of a bell-toad (Bombina) in the province of Yunnan, near Tong Chuan Fu, at an altitude of about 6,000 feet. This new species, Bombina maxima (Boulenger), thus indicates the central form from which both the European and the Korean bell-toads have 'sprung. Confirmatory of this, it may be mentioned that the new species in most essentials agrees with Bombina orientalis and B. salsa, the latter being the more southern and, in my opinion, the more primitive of the two European species.

The discovery of this species lends further weight to the theory propounded by me for the migration of this genus' in the following terms:

* Résumé published in Amer. Geogr. Soc. Bull., XXXVII., February, 1905, pp. 91-93.

? In the résumé quoted ‘southwest' through a lapsus or misprint.

3 L. c., p. 93.

HYDRATION CAVES. The conclusions set forth in my paper 'On the Origin of the Caves of the Island of Put-in-Bay, Lake Erie.'1 were based mainly upon observations, made last year, in Perry's Cave. The conditions, however, which exist on the island, led me to believe that the hydration of anhydrite has played an important rôle in the formation of all the caves. At that time I was able to visit three of the four caves open to the public, namely, Perry's, Kindt’s and the Crystal Caves. Concerning the other cave. Daussa's, the following statement was, however, made in the paper referred to above: “But inasmuch as this cave is in very close proximity to Perry's Cave, the above explanation, no doubt, also applies to it.”

During another visit to the island several weeks ago, Daussa's Cave was visited and it was noted that the fitting of the roof and floor is to be observed fully as well in this cave as in Perry's, leaving, therefore, no doubt whatever as to the origin of the same.

From the general topographic features of the island and the mainland in that vicinity

especially that which is known as Catawba Island—one is led to believe that careful searching should reveal more of these interesting caves, which differ so much in their origin and structure from the ordinary solution cave, that I would suggest they be termed

? American Geologist, XXXV., 167–171, March, 1905.

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