116 



THE EXTINCT BATEACHIA, REPTILIA 



L. macropus one-half, and Coelosaurus antiquus one fourth or fifth the size, whose remains 

 so far as they go indicate an identity of habit. Deslongchamps says of Poecilopleurum 

 bucklandii that it "could project itself with prodigious force, as a, spring which unbends 

 itself; but this could not have been on a solid surface, since the fore limbs are too weak 

 to resist the shock of the fall of such a heavy body." He supposed it to be marine in its 

 habits, accustomed to battling a, stormy sea. However his objection to leaping on land is 

 obviated by our hypothesis of its erect attitude, and its exclusive use of the hinder limbs, 

 the weight always falling on the latter. 



The disproportion between the fore and hind limbs of the Tguanodon, together with 

 the compressed form of the tail suggested to Prof. Owen an aquatic habit, a relation of 

 proportions of limbs to habit seen in the tailless Batrachia. The discovery of the massive 

 short-toed foot of tin; Iguanodon subsequently, has lent little countenance to the supposi- 

 tion of its entire adaptation to aquatic life. Dr. Lcidy has regarded the still greater dis- 

 proportion in the case of the Hadrosaurus as an index of a habit like that of the Kanga- 

 roos (Macropus, etc.), and that that mostcr rested in an oblique position on the hind limbs 

 and tail, and reached upwards with its muzzle and short lore limbs to the foilage on which 

 it fed. He seems also to have regarded it as aquatic as lie adds, "on the shores of the 

 ocean in which it lived." These genera could not have been aquatic in any great degree, 

 as the form of the toes was too stout, and they could have been too little separated to 

 allow of a natatory web. 



The bulk of the species, as compared with that of Hadrosaurus, illustrates again the 

 law observed in the relation between Felis and Bos, and the other raptorial and herbivor- 

 ous Dinosauria. 



In the same chocolate greensand bed the workmen found a femur of Hadrosaurus 

 foulkii, smaller than that described by Dr. Leidy; also portions of Mosasaurus dekayi. 

 Either on the chocolate or in the green stratum above it, remains of Bottosaurus harlani, 

 Ilyposaurus rogersi Owen, and Holops gavials of perhaps four species, with Cimoliasaurus 

 magnus Leidy, were found. 



The only molluscs which occurred with the remains of Laclaps were Baculites ovatus 

 and Cucullaea vulgaris. Ten feet above is a stratum of Ostrca vesicularis and Terebratula 

 harlani. 



> 



Synonymy. — The only doubt as "to tho proper name of this genus, has arisen with reference to the description 

 of the genus Dinodon by Leidy. I have cleared this matter up in Silliman's Journal, 1808, p. 415, as follows : 



Tn the Transactions of the American Philosophical Society, xi. p. 148, Dr. Leidy describes a, large, carnivorous 

 reptile allied to Megalosaurus, under the name of Dinodon Jiorridun. lie assigns to it, with some expression of 

 doubt, teeth of two distinct forms, viz : some having a lenticular transverse section, with cremation on the two 

 margins in part, and others having a lenticular section truncate to a greater or less degree, in place of one of its 

 angles, and therefore eremite on three edges in part. 



