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In the selachians, its close association with ulation or experimental study difficult withthe main olfactory and its distribution within out giving injury to the olfactory. the olfactory cup, might give ground for the It is doubtful if any trace of it be preserved suggestion that it is a radix mesialis of the 'in higher vertebrates. Whatever its original olfactory nerve. This, however, appears to function may have been, it was in some way me not well founded, since the nerve has no superseded in the evolution of animal life, con nection, at any time of its growth, with and having first lost its importance, it thereolfactory glomeruli. Even if it be one of the after disappeared. I have looked with espeolfactory bundles in an unusual position, its cial care for it in a number of amphibians. method of origin, and difference from all other and teleosts, and in the chick. Both embryolfactory radices would still justify the use of onic and adult stages have been examined in the designation “new nerve.'
Necturus, Amblystoma, the frog, the toad, the It is a relatively simple ganglionated nerve trout, the catfish and the chick, but in none that has apparently undergone little modifica of them has the nerve been found. tion. This, in itself, is a very notable cir- From any point of view, it is extremely cumstance, on account of its position on the interesting that we have preserved so fully in brain in a region of extreme modification. selachians and Dipnoi a ganglionated nerve Since it has remained in a relatively archaic in front of the optic, bearing in its anatomy condition, we may conclude that its function testimony as to its ancient features, but of has not been greatly elaborated. It may have which all traces have disappeared in higher been largely supplanted by the development animals. of the olfactory, or some of the branches of NotE.—Since the above was sent to the the trigeminus.
printer the 'Nervus terminalis' has been obWhen all circumstances of its structure and served in two rare selachians of ancient type development are taken into account, it seems -Chlamydoselachus and Mitsukurina. Proto me not unlikely that we have here the fessor Burt G. Wilder noted its occurrence in remnant of a very ancient nerve, whose orig the former, photographed it, and, subsequently, inal function is unknown, which in the proc sent me a portion of the brain embracing the ess of development has been reduced to sec nerve. In Chlamydoselachus it is similar in ondary rank, through the prodigious develop- position and anatomical features to the nerve ment of adjacent nerves and brain territories. in Hexanchus. It is connected with the foreIt has been shown that this nerve precedes
brain, within the median furrow, and upon the olfactory in embryonic origin, but the the terma about midway between the dorsal assumption would not be justified on this
and ventral surfaces. It runs directly to the account, that it is, therefore, older in phylo
olfactory cup. Near the base of the cup it genetic history, though such may be the case.
has an enlargement which, upon microscopic Its development in so many adult selachians
examination, proved to contain ganglion cells. would indicate that it is still functional,
As in Hexanchus, the main branch of the though reduced to a subsidiary rank.
nerve joins the median instead of the lateral Its ganglion will throw it among sensory
division of the olfactory fibers. nerves.
Professor Wilder also generously sent for But, while it has a sensory moiety, some
my examination the anterior portion of the considerations indicate that possibly it has
brain of Mitsukurina. In that rare and costly also a motor moiety. It has two roots, and
form the nerve is connected with the ventral in the skate, both medullated and non-medul
surface of the brain by two roots. It has a lated fibers have been observed in it.
very distinct ganglion lying on the olfactory It will be extremely difficult to determine
crus near the base of the bulbus. its physiological properties by experimentation. Its minuteness will render any manip
William A. Locy.
THE IMPORTANCE OF INVESTIGATIONS OF series of adaptive modifications of the cotyleSEEDLING STAGES.
don must be studied and arranged in series in The selection of the title, “The Importance agreement with their origin. of Investigations of Seedling Stages,' for This presents problems of no mean magnipresentation before the Section of Vegetable tude, physiological and morphological, the Morphology of the International Congress solution of which demands the accumulation carries with it the suggestion that it is the of a vast series of comparative data. Not intention of the writer to epitomize the recent only do the differing degrees of physiological attempts made to solve the problem of the specialization and morphological modification phylogeny of Monocotyledons by reference to of the cotyledon among Monocotyledons offer the anatomy of seedlings. The importance of problems of interest and importance, but the these investigations is beyond question and evolution of epigean and hypogean cotyledons the unexploited nature of the field has never' in the dicotyledons must be more satisfactorily been better expressed than by Miss Sargent, traced. If the close resemblance of many whose name occupies the most important place cotyledons to foliar organs is merely similar in these discussions, when she remarked that
structural adaptation to the same physiological while theoretically the embryo should offer function, the problem is not solved. but the characteristics of unusual taxonomic impor point of view is simply changed, since the tance, the only character so far of recognized
origin of such adaptations offers a group of value seems to be that employed in the separa
knotty problems which will require painstion of the two great divisions of the Angio
taking research for their solution. If the sperms.
cotyledons of many Onagraceæ are the homoBut this work has already been brought to
logues of haustorial organs, what is the nature the attention of botanists by foreign and and action of the correlation' which deAmerican writers and I speak of it only inci- mands that the portion of the cotyle dentally in passing to the consideration of lamina interpolated after exposure to the some other, though related, points, omitting, light shall have a structure and venation in of necessity, many interesting and suggestive close agreement with that of the true leaves illustrations which would require far too much
which follow rather than with the simple space for their adequate discussion.
form and tissue of many other cotyledons The recent revival and defense of the con
which are photosynthetically active for a long ception of the cotyledon as homologous with
time. the nursing foot of the lower forms rather
If, on the other hand, the old and generally than with foliar organs has suggested many accepted view is considered the correct one problems which will require a broad compara
and cotyledons are regarded as foliar in native study of all embryonic stages for solution.
ture, the series of forms is almost as puzzling The functions performed by the cotyledons
and as much in need of broad and comparative are various, the protection of younger em
investigation and arrangement. bryonic regions, the deeper planting of the
The morphology of the cotyledon has been young seedling, and above all, elaboration,
called into question through a consideration storage and absorption of food material, or in
of the relationship of Monocotyledons and other cases the cotyledons are merely vestigial
Dicotyledons. Apparent transitions from one structures. If it be maintained that the co
great group to the other have been discovered. tyledon is homologous with a more primitive
These apparent transition stages have been nursing foot and that the Dicotyledons are de
used to support two antagonistic views of the rived from the Monocotyledons by a bifurca
relationship of the two great groups. It is tion of an originally simple member, the whole
apparent that the special data so far secured * Read before the International Congress of Arts are very meager and, if it exists, the connecand Science, St. Louis Exposition.
tion between the two great groups must be
established by the discovery of a more complete series of transition stages. If, on the other hand, the forms to which so much significance has been attached are merely adaptations to peculiar life conditions, assumed by a plant at an exceedingly plastic stage of its development, the problem of the relationship of the two great groups seems to be farther than ever from a satisfactory solution.
The value of seedling characters for the tracing of phylogenetic development in families and lower systematic groups and an understanding of past changes both in the race and in its environmental conditions, has been emphasized by several writers. The most satisfactory results in this field are those obtained by Ganong and Cockyane, who have both worked principally with xerophytic forms which offer especially promising material for such researches, though here extreme caution must be exercised in deciding whether distinctive characters of the adult
It are not merely an expression of the direct influence of the environment upon a plastic organism, while the juvenile stages, owing to the different conditions of growth, are not subjected to these influences, and consequently all the potentialities of their primordia may be realized instead of intercepted and diverted or modified by powerful environmental influences. It scarcely need be suggested that here experimental morphology and ecology have before them material for a series of very interesting monographs.
A field in which results of especial interest may be expected is the comparative investigation of the later developmental stages within the same systematic group. For families Ganong has presented a masterly treatment of the Cactaceæ and Willis has accumulated some data for, and suggested the importance of, such work in the Podostemaceæ, while Miss Sargent's work on the Liliaceæ, when it appears, will doubtless represent the most extensive study of the kind ever undertaken In other families there is a large store of details waiting for supplementary researches and correlation. The results so far obtained show beyond question the interest, ecological,
morphological and phylogenetic, attached to the study of these groups. While I would not discourage the investigations of these larger groups, it must be admitted that in the present state of our knowledge there are many uncertainties connected with the generalizations concerning their phylogeny, and for the present especial importance should be attached to the investigation of the minor groups, particularly the genera. We have little right to assume the monophyletic origin of the most of the families, while with the genus this is more justifiable, though even here the greatest caution must be used. The embryonic stages, especially the later ones, should be of the greatest value in just this connection, for theoretically they ought to furnish us with an indication of form prevailing prior to the assumption of the more specialized adaptive characters.
But before we may draw conclusions as to the phylogeny of a group or conclude whether monophyletic or polyphyletic in its origin, from characters offered by the later embryonic stages of its members, we must first understand thoroughly the seedling and its reaction to all the factors influencing it. This is a field not for comparative work alone, but for physiological, ecological and experimental morphological investigations as well. Comparative studies are of the highest importance, but in this case they must be carried out upon material of systematically homogeneous nature. Until the appearance of Professor de Vries's epoch-making work no one has had available for study a series of forms unquestionably descended from the same ancestor. It is highly desirable that some one take up such types as the new elementary species of Professor de Vries for the purpose of ascertaining in how far there is a relation of ancestral characters and to what extent there is in the seedling a working back into the embryo of the characters of the adult. While the new species of Enothera described by Professor de Vries are the simplest systematic units, there are some very suggestive points to be found in his descriptions. The relative stages of development at which the differential
out of the questionicon of seed
to reconstruct the phylogenetic tree is quite out of the question.
In the examination of seedling stages, experimental morphology may find, as we have already suggested above, a fertile field for research in the determination of the degree of plasticity of juvenile and adult types. Some structures seem to be merely the result of the direct environmental influence, but others can not be modified by the changing of conditions. Some characters seem to be well fixed, while others are apparently merely the product of immediate influences of the environment. While phylogeny is the chief end, experimental morphology may find in seedling stages material of value for use in the formulation and solution of some of its fundamental problems.
J. ARTHUR Harris. MISSOURI BOTANICAL GARDEN AND WASHXGTOX UNIVERSITY, St. Louis.
characteristics of the new species make their appearance seem not without significance. In some there is an immediate and complete obliteration of the Lamarckiana characters, while in others, as in the 'atavism’of 0. nanella, the new characters replace those of the old only at a later period of development. Such cases as that of Trifolium, in which there was a working back into the embryo of the divided condition of the leaf as the number of leaflets characteristic of the mature plants increased offer suggestion for an important phase of statistical investigation. Investigations of the seedlings of some of the teratological "varieties' may be expected to yield results of great interest, especially when taken up from the experimental and historical point of view.
The chief object of the study of seedling stages, phylogeny, is dependent for its realization upon the validity of the recapitulation theory. In many cases this seems to hold, but, as pointed out above, a broad, comparative investigation of minor groups is imperative. Results of importance are assured. Developmental stages in the same group will generally show either a close similarity or present a series of perplexing differences. The conclusion in the one case will be that community of descent or identical environmental conditions are responsible. In the other case --and of this a considerable number of striking illustrations might be cited-polyphyletic origin of groups hitherto supposed to be monophyletic must be assumed, or the differences must be accounted for on the ground of adaptation or mutation and the importance of ontogeny as a key to phylogeny greatly restricted. With reference to seedling stages the statement that ontogeny recapitulates phylogeny must be made with great reserve. Doubtless it has here an evolutionary significance, but its application is a matter of serious import. It seems to me that in vast numbers of cases, the sweeping back of later developed characters in the nature of adaptations to environment or otherwise has oblit erated ancestral features, especially the superficial ones, to such an extent that an attempt
CURRENT NOTES OV METEOROLOGY, ('YCLONIC AND ANTICYCLOSIC TEMPERATURES.
A VERY useful summary of Various Researches on the Temperature in Cyclones and Anticyclones in Temperate Latitudes" has been prepared by II. Helm Clayton, of Blue Hill Observatory, and is published in Beiträge zur Physik der freien Atmosphäre, Vol. I., No. 3, 1905. It is probably known to men of science generally that one of the most interesting of present-day problems in meteorology concerns the origin of the cyclones and anticyclones which are such characteristic phenomena of the prevailing westerly wind belts, and constantly impress themselves upon us by reason of their control of our weather changes. Mr. Clayton presents an outline of the work of Hann, Dechevrens, Berson, Teisserenc de Bort, Rotch and others, including his own important results; points out the contradiction which exists between the conclusions of those who believe that cyclones are colder than anticyclones and those who find them to be warmer, and gives it as his opinion that both sets of investigators may be partly right. The author calls attention to the fact that those who have found the cyclone colder buve considered the temperature in relation to pressure without regard to time, while those who find the cyclone the warmer have, with one exception, considered the temperature with relation to the time of maxima and minima of pressure. A treatment of the data used by Teisserenc de Bort according to the method adopted by Clayton, leads the latter to results exactly the opposite of those obtained by the former.
In order to explain the results found at Blue Hill, Clayton has adopted the hypothesis that there are two causes for areas of low pressure: (1) an area of cold which contracts the air and tends to cause cyclonic circulations in the upper air, and (2) an area of warmth which expands the air and tends to cause cyclonic circulations in the lower air. These two cyclones are not necessarily connected. Both affect surface pressures, and both probably usually exist simultaneously within a few hundred kilometers of each other, and may form part of one system. The warmair cyclone of the surface has hitherto received the most attention. In this somewhat complex relation of upper and lower cyclones, as hypothecated by Clayton, we may find a satisfactory adjustment of conflicting views. METEOROLOGY AT COLORADO COLLEGE, COLORADO
SPRINGS. METEOROLOGY is developing under favorable auspices at Colorado College, under the direction of Professor F. H. Loud. The observatory building, erected in 1894, was the gift of Henry R. Wolcott, Esq., of Denver. There is a full equipment of meteorological instruments, some of which are exposed on the flat roof of the observatory, while others are placed on the roof of a neighboring building, east of the observatory and on higher ground. Tridaily eye observations are made, and from the self-recording instruments the conditions at the end of each hour during the twenty-four are determined. Monthly and annual summaries for 1904 are contained in the SemiAnnual Bulletin of the Colorado College Obsprratory (Colo. Coll. Studies; Gen. Ser., No. 16; Science Ser., Nos. 39-41; Vol. XI., pp. 119–190; April, 1905). In addition, Professor Loud discusses the topography of the district,
the diurnal changes of atmospheric conditions (illustrated by curves) and the cold wind of October 24, which came at the time of the usual morning increase of temperature and gave a daily maximum at 4 A.J. This wind, which was observed by two parties at high altitudes, began with a shallow flow of cold air from the north, in front of an approaching anticyclone. The cold stratum seems to have run beneath the quiet air of the region, lifting it and giving rise to a thin stratum of cloud which resulted from condensation by reason of ascent. Sometimes these conditions give rise to a slight fall of snow. A paper on “The Evolution of the Snow Crystal,' by John C. Shedd, embodies some results of studies made during the winter of 1901–02 at Colorado Springs. The author believes that the primitive crystal is, for the tabular form, of the “fern stellar' type, i. e., open in structure and with many branches, while for the columnar form it is the hollow column; that the solid tabular, solid columnar or granular forms are the final forms to which all others tend, and that there are two general processes of transformation from primitive to final forms. One process is that of accretion, and the other is that of transformation, in which the losses and gains result in a change in form, but not necessarily in amount of material.
NEOLITHIC DEW-PONDS. A RECENT study of Neolithic Dew-ponds and Cattle-ways,' by A. J. and G. Hubbard (London, Longmans, Green and Co., 1905), brings out some interesting evidence of the construction of dew-ponds by the early inhabitants of Great Britain. The process of construction was as follows: An exposed position where springs were absent was selected, and the hollowed surface was covered over with straw or some other non-conducting material. Over this was spread a thick layer of clay, strewn with stones. Condensation during the night from the lower air on the cold surface of the clay provided the water-supply for the pond. Springs and drainage from higher ground were avoided, because running water would cut down into the clay surface