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Show 1891.] MR. G. A. BOTJLENGER ON CHELONIAN REMAINS. 7 p. 15, R. 1499) comes nearest the existing T. hurum, Gray ; for skull which I now exhibit agrees in almost every respect with that of the Indian T. hurum, of which a specimen of the same size (half-grown) is figured for comparison (fig. 4). This is very remarkable, species of Trionychoids being so well characterized by their skulls; and had the fossil been obtained from the Pleistocene of India, I should have unhesitatingly pronounced it to belong to T. hurum. Four species appear to be well distinguished, from their shells, in the Hordwell beds, viz.:-T. barbarce, Ow., T. henrici,Ovf., T.incras-satus, Ow., and T. planus, Ow., the latter species being only known from the posterior portion of the carapace. It is just to this species that I should feel inclined to refer the skull, as it is the only one which, in the coarse sculpture of its dorsal plates, at all approaches the existing T. hurum ; and I am pleased to find that Mr. Lydekker expresses the view that the mandible alluded to above may possibly be referable to T. planus. It is, however, not possible to ascertain whether in the species with very coarse sculpture of the dorsal shield (T. planus) two neural plates instead of one are present between the first pair of costals, as in the Indian group to which T. hurum belongs ; let us hope that future finds may settle this point. In the meanwhile, this fossil skull (see fig. 5, p. 6), may be provisionally referred to T. planus, Owen. 3. On a Humerus of Eosphargis gigas, Owen, from the London Clay of the Lsle of Sheppey, Kent. The proximal end of the left humerus of an Athecan Turtle from the London Clay (Lower Eocene) of Sheppey, presented by J. Wickham Flower, is preserved in the Museum of the College of Surgeons, and was described by Owen (Descr. Cat. Foss. Rept. 1854, p. 3) as " the lower or distal end of the tympanic bone of the Croco-clilus toliapicus 1; it exceeds in size the corresponding part of the largest recent Crocodiles in the Hunterian Collection"2. This specimen may be safely referred to Lydekker's Eosphargis gigas, Ow., but belongs to an individual considerably smaller than any on record, the greatest diameter of the proximal end of the humerus being only 1 On this occasion, I would observe that C. toliapicus, Ow. (= C. spenceri, Buckl., = C. champsoides, Ow.), is no true Crocodilus, as it differs in its dental formula ( ^ t l Crocodilus having ^ ^ ) , the absence of a pointed process on the free border of the quadratojugal, and the large size of the mandibular vacuity, in all these characters agreeing with Biplocynodon, to which genus the British Upper Eocene and Oligocene Crocodile Alligator hantoniensis, W o od (= Crocodilus hastingsiee, Ow.), belongs. I regard Biplocynodon spenceri and B. hantoniensis as standing in the same relation to each other as the recent Crocodilus intermedins and C. pahistris. W e therefore know of no British Eocene or Oligocene Crocodilus, the remains hitherto referred to that genus belonging to Biplocynodon. 2 T w o other fossils are referred by Owen (I. c.) to the same Crocodile. His " portion of the left ramus of the lower jaw " I regard as a portion of scapula of Eosphargis; and his " another portion of the right ramus of the lower jaw " belongs to a Liassic Plesiosaurian. |