Sphenozamites robustus, n. sp. Figs. 12-14.

Frond large, form unknown, pinnules one to four inches in length, ovoid or lanceolate in outline, narrowed and thickened at the base, pointed at summit, margins entire, thickened; nerves few and strong at base, forking and multiplying above, diverging to all parts of the margins, not converging at summit.

Quite a number of pinnules, all more or less imperfect, of this remarkable cycad, are contained in the collection brought by Mr. Leggett from Honduras. They vary considerably in form and size, but present characters which are somewhat at variance with those of any other fossil cycads known, though they most resemble those of some species of Sphenozamites. They are distinctly wedge-shaped at base, expanding to an unsymmetrical ovoid or lanceolate outline above with radiate and divergent nerves, which below are few and coarse, above very fine. In the larger pinnules the summit is pointed and in some cases unsymmetrically acute. If, as seems probable, the curvature of the pinnules was toward the summit of the frond the general aspect of the plant may have been much like that of Sphenozamites Geylerianus Zigno (Flor. Fos. Oolitica, vol. ii, p. 107, Pl. XXXIX, figs. 1, 2) only it must have been much larger. Fragments of the lower portions of the pinnules are not unlike some of the specimens of Podozamites latipennis figured by Heer (Flor. Fos. Arctica, vol. vi, Pl. xiv and xv), but the nerves are not parallel with the margins nor do they converge at the summit.

Among other described fossil cycads none seem to approach so near to the plant before us as the species of Sphenozamites with entire pinnules, and here the resemblance is so close that I have felt justified in referring it provisionally to that genus.

Sphenozamites? grandis, n. sp.

Pinnules four inches or more in length, oblong or lanceolate, obtuse, narrowed and thickened toward the base, nerves strong, straight, simple or rarely forked, part diverging from the base to the margins, part running parallel to the upper extremity.

Of this plant we have numerous fragments in the collection, but none of them complete organs. The pinnules were four or five inches in length by an inch in width and are conspicuous for their clear and strong nervation, which is radiate from the base. They undoubtedly represent a large cycad, hitherto undescribed, but it will be necessary to have complete pinnules to decide whether it should be referred to Sphenozamites, Otozamites, or Glossozamites. It must have been much like the plant described by Feistmantel (Foss. Flora of the Lower Gondwanas, p. 19, Pl. xx, figs. 4, 5) under the name of

Glossozamites Stoliczkanus, and should doubtless be included in the same genus, but it seems to me very doubtful whether that should be the same as that for which G. Zitteli stands as the type.

Anomozamites elegans, n. sp. Figs. 6-8.

Fronds narrow, elongate, delicate, from half an inch to one inch in width, length unknown; midrib straight and persistent but slender; pinnules near base in close contact, as broad as long, forming a scolloped margin to the midrib; above subquadrate or rhomboid in outline with the lower external angle rounded, the upper subacute, produced; nerves fine, simple or forked, parallel with the upper margin of the pinnules.

Among the fossil plants brought from San Juancito by Mr. Leggett are a number of narrow fronds with subquadrate pinnules which evidently represent the group of cycads which runs through the Mesozoic rocks of Europe, beginning with A. minus Brgt. in the Rhætic and ending with A. Schaumburgensis Dunker, in the Wealden. It is perhaps most like A. gracilis Nathorst (Sveriges Fossila Flora, p. 43, Pl. XII, figs. 4-12), but from this as well as from the other species referred to it is distinguishable by the more pointed and produced upper angles of the pinnules. Figure 6 apparently represents the basal portion, fig. 7, the middle and fig. 8, the summit of these fronds.

Pterophyllum propinquum? Goepp.

Frond large, pinnules subalternate, linear, long-pointed, four inches in length by one-half an inch in breadth at base, gradually narrowed to the acute extremity, springing from the rachis at right angles; base sometimes slightly rounded and narrowed, oftener attached by its entire breadth; nerves distinct, simple, parallel.

The specimens I have of this plant are too few and imperfect to make a comparison with the species described by Goeppert entirely satisfactory. The bases of some of the pinnules seem to be slightly contracted and with a few divergent nerves. If this should be shown by better specimens to be a constant character it would bring this plant into Zamites and into close relationship with Z. Renevieri Heer, of which the size and general aspect must have been very similar.

Pterophyllum Braunsii? Schenk.

Of this plant one complete pinnule and several fragments are contained in the collection, but are scarcely sufficient for accurate determination. It is evident, however, that we have here the remains of a species of Pterophyllum or Nilssonia remark

ably like, if not identical with that described by Schenk (Flora der Grenzschicten, p. 168, Pl. XL, figs. 2, 3) under the name of Pterophyllum Braunsii. The pinnules were attached by the entire base, are an inch in width by two and a half inches in length, the summit is obliquely rounded, the nervation fine, parallel and simple, sometimes dotted as shown in Schenk's figure.

A nearly related plant to this is Pt. princeps Oldham and Morris (Fossil Flora of the Rajamahal Series, p. 23, Pl. X-XIII), but our material is too imperfect for the determination of specific identity or difference.

Dioonites longifolius? Emmons.

An imperfectly preserved fragment from the middle of a frond is all we have of a plant that if not identical with must have been very closely allied to that described by Emmons (Amer. Geol., Part VI, p. 116, fig. 83) from the Upper Triassic strata of North Carolina.

Dioonites Carnallianus? Goepp.

This plant is imperfectly shown in the collection made by Mr. Leggett, but is plainly distinct from any other with which it is associated. It evidently belongs to a group of cycads which form a marked feature in the Rhætic flora and of which Pterophyllum Carnallianum of Goeppert may be taken as a type. In this group the fronds are broad, the pinnules very long and narrow, attached to the rachis by the entire bases, which are sometimes slightly decurrent, but never expanded upward nor connate; the nerves are sharply defined, but fine, simple and parallel.

More material will be required before the identity of the Honduras plant with that to which it is provisionally referred can be asserted. It is, however, a distinct element in the San Juancito flora and deserves mention from its relationship with the group of Rhætic cycads with which I have compared it.

Nilssonia polymorpha Nathorst.

Only a few fragments of this plant are contained in the collection made by Mr. Leggett, but these are quite sufficient to show its distinctness from any other with which it is associated and to determine its generic relations. Whether the segments of the frond were united, as is usual in N. polymorpha, can only be determined from other collections, but this is not indicated by the specimens before us; the pinnules being entirely distinct and separated.

Fragments of the species of Anomozamites found with this might at first sight be confounded with it, but in these the

divisions of the frond are not carried down to the rachis and the nervation is much finer. A similar and perhaps an identical species of Nilssonia occurs in the Triassic coal basin of Sonora, Mexico.

Nöggeruthiopsis, sp.

Among the fossil plants from Honduras, as well as those collected by Remond in Sonora, are some which perhaps represent different genera, certainly different species, but which are alike in having spatulate or wedge-shaped leaves several inches long, traversed by a fine or coarse parallel nervation. Part of these undoubtedly belong to the genus Nöggerathiopsis so common in the Mesozoic rocks of Australia and India, but they are too imperfect to be satisfactorily identified or described. Some of them must have been a foot or more in length, and they differ considerably in shape, either expanding rapidly or being long and strap like. The nervation is sometimes so fine as scarcely to be visible, in other cases very coarse, but exact.

Several ferns are contained in the collection, but the specimens are too much weathered and decayed to permit of their identification or satisfactory study. All these, with many other things of which only fragments have been obtained by Mr. Leggett, will doubtless receive attention and elucidation from those who hereafter may have an opportunity of studying the rich flora which it is the object of this paper to bring to the notice of geologists.

This discovery of a Triassic flora in Honduras is a matter of special interest, as nothing of the kind had before been met with in that section of the globe; but it is only another illustration of the uniformity of the vegetation of the world during the Triassic age. This uniformity was, however, only a development of the systematic progress of plant life. The reign of Acrogens ended with the Permian. The Rhætic epoch was therefore about the middle of the reign of Gymnosperms. No Angiosperms were yet in existence, for they began in the Cretaceous. Hence, after the decadence of the Lepidodendra, Sigillariæ, Calamites and Cordaites, the whole world was opened to occupation by the new dynasty of plants, the Gymnosperms (Cycads and Conifers) and the peculiar group of Mesozoic ferns. They lost no time in entering upon their promised land and spread until they covered all portions of the, to them, habitable globe.

Where the Gymnospermous flora originated, or how it was developed from the Acrogens, if it was so developed, and through the exercise of what elements of superiority it superseded them, we are as yet in ignorance. It is, however,

a matter that may well excite our wonder that, migrating such immense distances from their places of origin, through every phase of soil and climate-through all the zones of the Eastern Hemisphere, and nov as we learn from this group of Honduras plants, through the New World-they marched, holding so firmly to their original group of characters, generic and specific, that wherever we open their tombs we recognize them instantly as old friends. In their long marches some perished by the way, and here and there their numbers were recruited by new forms, imported or developed; but the leading members of the troop, in virtue of some occult protection against outside influences, preserved almost without alteration all the complicated characters of their vegetative and reproductive systems.

We shall look now with eagerness to South America for the identification there of this Mesozoic flora, which we have found in full development in Virginia, New Mexico, Sonora, and now in Honduras. It had before been recognized in Australiawhere it seems to emerge from the Paleozoic flora and perhaps began-New Zealand, India, Tonquin, China, Turkestan, and various parts of Europe.

Hence, with its discovery in South America we shall see it reaching as a girdle around the entire globe. This girdle was not put around the earth, however, like Puck's, in forty minutes, but in thousands and millions of years; for when we realize with what slowness the migration of plants takes place, we must recognize in the universal distribution of the Carboniferous and Mesozoic floras evidence of the lapse of intervals of time of which the duration is simply immeasurable to us.

ART. XXXVIII.—On the Circular Polarization of certain Tartrate Solutions. I. By J. H. LONG.

THE change in the circular polarization of a solution of an active substance by admixture with an inactive one has been studied in several cases. Müntz found, for instance, that the specific rotation of cane sugar for a concentration of 20gm in 100cc changed from [a]D = 66·°5 to [a]D = 66°3 by addition of 55m of NaCl, and to 61 °0 by addition of 20m. g

The same chemist and others have shown the effects of adding various substances to sugar solutions. In most cases a decrease in the specific rotation was found.

Under certain circumstances the addition of an inorganic substance converts an inactive organic body into an active one, as in the case of mannite when in solution with alkalies, weak