Crocodilus, and the arrangement of the teeth and their relative sizes, so far as it is possible to ascertain the facts from the skull under consideration, was the same as in Crocodilus. Three successional teeth are preserved on the left hand side of the upper jaw, and the crowns of two larger teeth were found detached from the skull and in the matrix beside it, evidently belonging to the

O

C

same specimen. These teeth differ somewhat from those of the recent genus Crocodilus in being somewhat more compressed and trenchant and not as conical. They are not, however, as obtuse as the teeth described by Owen as belonging to the genus Goniopholis, although upon the crown, particularly upon the inner surface, they distinctly reveal the neatly defined longitudinal ridges, which appear to agree with the description given by Owen. The two lateral ridges, one anterior and the other posterior, midway between the convex and concave surfaces, are in both cases sharply defined, and even more sharply than in the genus Crocodilus. The larger of the teeth that have been preserved appears to the writer to be, reckoning from the front, No. 10 in the left series.

FIG. I.

a, Tooth of G. Gilmorei, nat. size; b, outline of section at base; c, outline of section at middle of crown.

DIMENSIONS OF THE SKULL OF GILMORE'S CROCODILE.

Length of skull on median line..........

66

from posterior extremity of quadrate to end of snout.. Transverse diameter of snout across premaxillaries

66

at junction of maxillaries and premaxillaries 4.00 "skull at front of orbits.......

10.80 "

The specific characters by which this species may be distinguished from the other species of the genus Goniopholis described from North. America appear to be the very closely pitted superior surface of the bones of the skull, the existence of the elevated ridges partly sur

rounding the supratemporal foramina, and the less obtuse, elongated, and compressed shape of the teeth.

The writer assigns the species to the genus Goniopholis with doubt: first, because no vertebræ were collected, and therefore it is unknown whether the centra were amphicœlous as in Goniopholis or not; and, secondly, because the longer, less obtuse, and more trenchant teeth do not fully accord with the generic description given by Owen.

X. PROCAMBARUS, A NEW SUBGENUS OF THE

GENUS CAMBARUS.

BY A. E. ORTMANN, PH.D.

In a paper just published (Proc. Amer. Phil. Soc., vol. 44, 1905, p. 91), the present writer has divided the genus Cambarus into four subgenera Cambarus (sens. strict.), Cambarellus, Faxonius, and Bartonius. The first of these (Cambarus) is framed to receive the first and second group of this genus, as distinguished by Faxon (excluding C. pellucidus, which I refer to Faxonius).

In the paper referred to (p. 99), the writer has indicated, that the association of Faxon's first and second group into one subgenus might possibly not be entirely correct, but, that a division according to the number of legs which possess hooks on the ischiopodite, as introduced by Faxon, does not exactly correspond to the natural affinities. He also pointed out, that possibly the shape of the copulatory organs of the males of certain Mexican and Cuban species is more important in this respect.

The Carnegie Museum has lately purchased from Professor J. S. Hine, Columbus, O., a number of specimens of a new species of Cambarus from Guatemala (Acc. No. 2778; Cat. Nos. 74,560 and 74,561), belonging in this group, which, in the paper referred to, has been designated as the digueti-group (of the section of C. digueti), containing hitherto three species (digueti, mexicanus, cubensis). An examination of the copulatory organs of this new form, and their comparison with the figures of these organs of C. carinatus, digueti and cubensis, with the description of these organs in C. mexicanus, and with a male cotype of C. digueti, kindly presented by Professor E. Bouvier, of Paris, has led to the conclusion, that all these species, as well as the new one to be described herein, possess a type of male copulatory organs, which is quite peculiar, and differs considerably from that seen in other species of the subgenus Cambarus (type: C. blandingi).

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The description of this organ, as given by Faxon for his first and second groups, and by the present writer for the subgenus Cambarus, does not apply at all to these Central American and Cuban species.

An attempt has been made, in the paper referred to, to also include these forms in Cambarus, but, as is now evident, this is impossible. The material at hand when the paper was written was too poor (only one male of the second form of C. digueti) to decide the question, and, moreover, the description of these organs in C. mexicanus was not well understood, since no figure had been published.

However, Faxon's description of the male organs of C. mexicanus suddenly became clear to me when I compared it with the new species, and plainly these organs in these two species are very similar. Since good figures of those of the other two species have been published, it is now possible to give a correct account of these organs, and to point out their chief peculiarities.

Faxon's description of the male copulatory organs in his first and second group is as follows: "Outer part truncate at the tip, and furnished with one to three small recurved teeth; inner part terminated by a short acute spine, which is generally directed outward."

For the subgenus Cambarus, I have given the following characters of the male organs: "Sexual organs of male stout, more or less straight, and comparatively short, truncated or blunt at the tip, the outer part ending in one to three horny teeth, which are sometimes recurved, or compressed, or plate-like, and are always sharply distinguishable by means of the blunt end. Inner part terminated by a shorter or longer acute spine, which is sometimes distinct from the tip of this part, so that it appears two-pointed."

This latter description was framed with the desire to make it fit the species of the digueti-group; but it neglects the fact, that in these species the outer part of the male organs does not possess any horny teeth, as is generally the case in species of the type of blandingi. In the species of the digueti-group, it is the inner part that possesses, in the male of the first form, a single horny spine, which has a variable position in the different species, but is always highly characteristic for one and the same species. It has taken me some time to ascertain this fact; indeed, I admit that I may be mistaken in so far as that there is a remote possibility that this horny spine belongs to the outer part, since in the new species to be described here, its position is just at the point where the two parts (inner and outer) become distinguishable at the anterior margin of the organ; but after examining the condition in second form males of the new species and of C. digueti, I feel rather sure that this accessory tip, which is not horny and spiniform

in this case, but tuberculiform, belongs to the inner part. (Compare also Faxon's figure of C. carinatus digueti, Proc. U. S. Mus. 20, 1898, pl. 63, f. 2.)

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Thus this organ is fundamentally different from that of the subgenus Cambarus as represented by its type (C. blandingi), and, moreover, it possesses at its anterior margin, not far from the tip, a peculiar angular projection, which I have called the "shoulder." Such a shoulder is found in a few cases in other species belonging to the subgenus Cambarus (C. clarki and troglodytes), and in numerous species of the subgenus Faxonius (section of C. propinquus); but here it always has a different position, being quite remote from the tip of this organ.

Thus I think we are justified in emphasizing this peculiar feature of the male organs by creating for it a separate subgenus, for which the name Procambarus is proposed, and we consequently have now five subgenera within the genus. The diagnoses of the two first are as follows.

Procambarus subgen. nov.

Sexual organs of male stout, more or less straight and comparatively short, rather blunt at the end, but not truncate. The two parts in close opposition up to the tips. The outer one ending bluntly, without horny teeth; the inner one being more or less similar to the outer one, but possessing in various positions one horny spine. Anterior margin with a shoulder near the tips. In the male the third pereiopods have hooks.

Species: digueti, williamsoni, mexicanus, cubensis.

Cambarus (Ortmann sens, restrict).

Sexual organs of male stout, more or less straigh and comparatively short, very blunt, or truncated at the end. The two parts in close opposition, with exception of the terminal spines. The outer part ending in one to three horny teeth, which are often recurved, or compressed, or plate-like, being sharply distinguishable from the blunt end. Inner part terminated by a shorter, or longer, acute spine. A shoulder on the anterior margin is rarely present, and it is, if present, quite remote from the tip. In the male the third, or the third and fourth, pereiopods have hooks.

The diagnoses of the other three subgenera: Cambarellus, Faxonius, Bartonius, do not require any change.