Page:Synopsis of the Exinct Batrachia and Reptilia of North America. Part 1..pdf/90

 84 THE EXTINCT J3ATRACHIA, REPTILIA between them on the middle line another whieh together enclose two shallow concavities. Supereiliary margins raised, the cranial table quite flat. The margin of the quadratojugal bone projects strongly. The scales of the limbs are all smooth, and those of the dorsal region with very low keels. The sides have four longitudinal rows of ovate scales separated by seareely defined smaller ones. The abdominal plates are longer than broad, and are in twelve longitudinal rows. Dorsals in seventeen transverse series from interseapular to °rural region. The lateral erests of the tail are only obtuse keels ; they unite on the thirteenth annulus behind the vent inclusive. Color above dark brown, almost black on the upper surfaces of the head. The tail is paler, of a light olive brown. Lower sur-faces everywhere bright yellow. including the entire lower jaw and margin of the upper. Eyelids and a band through ear yellow, the former with a black spot above. Remarks.—This interesting addition to our knowledge of the Beptilia was made by Schulte Buekow of New York, while on a visit to the interior part of the course of the Magdalena river in New Grenada. This naturalist has also enriched our collections with other interesting vertebrata, of that region, both living and dead. OS'I'EOLAEMUS, Cope. Proceed. Aead. Nat. Sei., Phila., XII, 550, 1860. ilakrosia, Gray Ann. 3Iag. Nat. Hist., 1862, 273. As this genus has been variously understood, since its first publication, I take the present opportunity of quoting the original description, and adding such observations as are necessary to a full comprehension of the species embraced by it. "Osteolaimus, Cope, was characterized as a genus of Crocodiles presenting several points of analogy to the Alli-gator. The nasal bones were prolonged anteriorly, and uniting with the short spine of the intermaxillary, divided the external nasal orifice, as in the genus Alligator. The eyelids were entirely osseous as in Caimans There was no transverse bony ridge between the orbits. The dermal plates upon the tail, extremities, and the thorax, were more or less completely ossified ; upon the gular region the ossification was most complete, the shields having a coarse natural articulation. "The digits of the posterior extremity were very slightly webbed. " Cervical plates distinct from the dorsal. "Mr. Cope alluded to the remarkable extent to which ossification was carried in this genus. The cranium was much more rugose and pitted than in the adult speeimens of much larger species, and the crotaphite foramina were roofed over by bone. The latter peculiarity was sometimes observed in the genera Jacare and Caiman. " The osseous gular and thoracic buckler was also similar to that exhibited by those genera, and by the extinct " Crocodilus" Hastingsiai Owen, the existence of which has been shown by Professor Huxley. "Two specimens were exhibited : one a skin brought from the Ogobai river, Western Africa, by Mr. P. B. Du Cbaillrr ; the other, the skull of a half grown individual, obtained from the Museum of the Pennsylvania University, "These Mr. Cope regarded as belonging to a species hitherto unknown, and which he proposed calling Osteolae-mus tetra spes." Several descriptions of species of this genus have been published under different names. It is a matter of question whether all do not relate to one species. A young one was described by Murray, whose muzzle was of course much broader in relation to its length than in the adult. An adult was afterwards described by Lilljeborg with the relatively longer muzzle. It differed from that described by Murray hi having but four rows of dorsal shields, and but two pairs of eervicals ; iu the latter there are three pairs of cervical:: mid six rows of dorsals. My type specimen, brought from the Ogobai by DuChaillu possesses six rows of dorsals, and only four cervieals, thus combining the characters of the two. Gray, however, who has seen Murray's type, says there are but four rows of dorsal plates ; in the Ogobai specimen one row has but five, and in three others the two outer are nearly united ; so I am disposed to think that no great importance is to be attached to this character. Murray's specimen has the relatively enlarged brain cavity of a young animal elongating the table of the cranium ; Lilljeborg's, which is adult, maintains this character more than our specimens do. Gray gives a figure of the cranium of the adult, which eoincides with two crania, in our Museum, one of the above mentioned specimen, while both agree in the proportions of the muzzle with that described by Lilljeborg. The last, however, differs from all these in having the table of the cranium but little