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JUNE 11.

The President, Dr. RUSCHENBERGER, in the chair.

     Twenty-five members present.

     Prof. COPE offered some remarks on the discoveries recently made by Prof. Marsh as to the structure and characters of the Pythonomorpha, based especially on material recently obtained by him in Kansas. As the writer had recently passed in review much similar material, he was much interested in Prof. Marsh's conclusions. These, he said, were of importance. In the first place, he had ascertained that what was formerly supposed to be the inner side of the quadrate bone was the outer side, a conclusion Prof. Cope thought entirely consistent with the other known relations of the parts.

     Secondly. He had discovered the stapes, and had entirely confirmed the opinion of the speaker, which Prof. Marsh had apparently overlooked. This was stated as follows:¹ the quadrate "is characterized by the presence of an oval pit. ... Its use is uncertain, but there is some probability that it received the extremity of an osseous or cartilaginous styloid stapes. A groove on the under side of the suspensorium, would accommodate such a rod, and in a position nearly similar to that which it occupies in many of the Ophidia." It is in precisely this position that Prof. Marsh is so fortunate as to have discovered it.

     Thirdly. Prof. Marsh believes that he has found the columnella. I have supposed it to be wanting, from the absence of its usual points of attachment on the parietal and pterygoid bones. It remains to compare the bone found by Prof. Marsh with ali- and orbito-sphenoid and ethmoid ossifications found in many saurians.

     Fourthly. Prof. Marsh has observed the parieto-quadrate arch described by the speaker, and makes the interesting observation that it is formed of three elements, the median connecting the parietal with the opisthotic. This piece, he says, is "apparently the squamosal; "as the latter bone completes the zygomatic arch, it cannot occupy a position in the parieto-squamosal, unless it sends a branch in that direction.

     Fifthly. He discovers the malar arch, proving it to be incomplete and supported by the postfrontal bone. Prof. Marsh also observes an ossification in the glenoid cavity of the opisthotic, which he regards as the pterotic (of "Huxley," which should be Parker),

an identification which cannot probably be maintained. The connections of the pterotic, where present, are very different. The bone in question is present in Edestosaurus tortor, Cope.

     Sixthly. Prof. Marsh completes almost entirely our knowledge of thee anterior limbs. The previous descriptions of these members in Clidastes propython, Cope, Holcodus ictericus, Cope, and other species, had left the number of phalanges and their relative positions, as well as those of the carpal, uncertain; these points are now happily supplied by Prof. Marsh's important researches.

     Seventhly. He has done much for the pelvic arch and hind limbs. He was the first to announce the existence of both, and actually described the pelvis of Edestosaurus dispar; the speaker, however, first described the hind limb in Liodon crassartus and L. dyspelor, Cope. Prof. Marsh is in error when he says the "absence of these extremities in the Pythonomorpha was considered satisfactorily established." I had never stated that they were certainly absent, and the last time I wrote observed that this order "possessed an anterior pair only, or with the posterior pair so reduced as to have been insignificant."¹ They appear, according to Marsh, to have been relatively small in some of the genera.

     In Liodon dyspelor, Cope, the anterior are the smaller. Prof. Marsh lays students under especial obligation for his determinations of the pelvic elements and the excellent figures of all the parts connected with the support of the hind limb. His figure of the fore limb is also highly important, as it "will be difficult soon to duplicate his beautifully complete specimen.

In subsequent pages there are six additional species described, bringing up the number from the Kansas Cretaceous to twenty- three. Two new genera are proposed, viz., Lestosaurus for those previously referred by myself to Holcodus, Gibbes, and Rhinosaurus for species allied or belonging to Liodon. As to the former, it is no doubt a well-marked genus, and I am willing to believe Prof. Marsh's opinion, that it will not include Gibbes' Holcodus acutidens, will turn out to be well founded; but there is, on the other hand, insufficient evidence to show that it is not Platecarpus, Cope. If Liodon curtirostris be referred to it, it will very probably prove to be Platecarpus, as that species presents palatine teeth, much as in P. tympaniticus, and the pleurodont character is not wanting in some of the other species. Rhinosaurus includes such species as Liodon proriger, Cope. As the name has been used two or three times before, it may be altered to Rhamphosaurus, but I have always had doubts that the conic projecting snout would distinguish the species generically from the true Liodon, with which it agrees in dentition. The type of Liodon, L. anceps, ord., is, however, very little known.