History of British animals - University of Guam Marine Laboratory

154 REPTILES. SAURIA.1825, for the reception of the bones of an animal found in theironsand of Tilgate Forest, near Cuckfield, in Sussex. Thisreptile appears to have been herbivorous, and to possess a closeaffinity with the recent Iguana of the West Indies. Mr Mantillconsiders the animal as having; been upwards of 60 feet inlength.— Annals of Philosophy, March 1825, p. 223.ENALIO SAUKI.In this group of Saurian Reptiles, instituted in a paper by H. T.de la Beche and the Rev. W. D. Conybeare, Geol. Trans, v. 559,the extremities are four in number, terminating in paddles, composedof a series of flat polygonal bones, fit constituting organs for swimming,but incapable of executing progressive motion on the land.The eyesare large, and the sclerotica is strengthened by a circle ofosseous pieces ;— a character which establishes an affinity with birds,lizards and tortoises, to the exclusion of crocodiles and fishes.IV. Ichthyosaurus.— This genus, the characters of which havefrom time to time been developed by Sir E. Home, in the PhilosophicalTransactions of the Royal Society of London from1814 to 1820 inclusive, and more recently by Mr Conybeare,exhibits the snout of a dolphin, the teeth of a crocodile, thehead and sternum of a lizard, and the swimmers of a whale,with the vertebrae of a fish. The extremities have no distinctradius and ulna ;but the humerus supports immediately a numerousseries of polygonalbones. The anterior extremities arethe largest.Dentition like the crocodile, the young tooth growingup in the interior of the cavity of the old one, and, whenmatured, splitting,and causingit to fall. Teeth numerous.Vertebrae from 80 to 90. The following species have been established.1. I. communis Teeth with conical summits, moderately pointed, slight-\y bent and deeply striated. This is the largest of the species, and occurs inthe Lias. It is probably the one figured by Mr Young, Wern. Mem. iii.450. tab. xxii.p.2. I. Platyodon.—Teeth with compressed summits, with a sharp ridge oneach side.3. I. tenwrostris Teeth slender nose ; produced— Home, Phil. Trans.1819, tab. xv.4. I. intermedins.—Teeth more pointed, and less deeply striated, than in I.communis.These different species are distributed in the strata of the lias and ooliticformations. Dr Harlan has proposed to add another species to the Britishlist, which he supposes to have come from the neighbourhood of Bath or Bristol.It resembles the I. communis; but he says that the teeth ai*e moreaduncate, and the dental bone of greater relative thickness. He proposes toterm it I. coniformis.—J ourn. Acad. Phil. iii. p. 336. tab. xii. f. 6, 7 8. 5V. Plksiosaurus. — This genus was instituted by Mr Conybeare.With the swimmers of a whale, and the head of a lizard,