BOTTOSAURIJS. 13 



specimen was referred to an extinct species of Crocodile, which, in 1832, was indi- 

 cated in the Palseologica of Meyer, as Crocodilus Harlani. Subsequently, Dr. 

 Harlan, in his Medical and Physical Researches, published in 1835, named the 

 species Crocodilus macrorhynchus, by which name it is generally indicated by 

 systematic writers. 



The fragment consists of the greater portion of the right dental bone, and is 

 accompanied by a portion of the corresponding angular bone, apparently from the 

 same jaw. The specimens are black and heavy, and like many other of the Green- 

 sand fossils are infiltrated with sulphuret of iron, in consequence of the decompo- 

 sition of which they are in a less well preserved condition than formerly. 



The fragment of the dental bone, represented in Figs. 19, 20, Plate IV, is about 

 fifteen inches in length, and in this extent contains the remains of eleven alveoli, 

 which perhaps comprise the whole number except three or four. It corresponds 

 nearly in form and proportions with the homologous portion of the jaw of the 

 Crocodile or Alligator. The posterior portion of the symphysis is preserved ; and 

 reaching quite to it, along the inner side of the bone, is the sutural surface of the 

 splenial. The enlargements of the dental bone for the accommodation of the 

 canine and posterior largest teeth occupy nearly the same relative position as in the 

 Crocodile ( G. palustris), and are separated as in the latter by a cylindroid portion 

 of the jaw, which in the specimen measures two and a half inches in diameter 

 transversely, and about the same extent of depth. The outer surface of the bone 

 is abundantly supplied with unusually large vasculo-neural foramina. The remains 

 of the alveoli, so far as one can judge in their mutilated condition, appear to indi- 

 cate a succession of teeth related to one another in size nearly as in the series of 

 the Crocodile or AUigator. 



The fragment of the angular bone, represented in Fig. 21, Plate IV, is a portion 

 intermediate to the oval angulo-dental foramina and its posterior prolongation. Its 

 outer surface is vertical, and foveated, and its base or under border is convex, and 

 measures two and a quarter inches in thickness. 



Of three teeth which accompanied the fragments above described two are much 

 mutilated, one only having an entire crown. One of the mutUated specimens 

 appears to have occupied the third alveolus, back of the canine, and was compara- 

 tively small. The other, represented by Fig. 8, Plate 9 of Dr. Harlan's memoir, 

 apparently occupied the eighth or ninth alveolus back of the canine. It possessed 

 a mammiliform cro^vn, from which the enamel is destroyed, and has a gibbous fang. 

 The third specimen is the penultimate or last tooth, represented in Figs. 11, 12, 

 Plate XVIII, and closely resembles the corresponding teeth of living Crocodiles. 

 The fang was gibbous ; and the crown is laterally compressed mammiliform, with 

 its outer and inner surfaces separated by a prominent ridge, and its enamel strongly 

 corrugated. The crown is six hnes high, eight lines and a half antero-posteriorly, 

 and six lines transversely. 



Upon the fossils above described, Prof. Agassiz infers Harlan's Crocodile to belong 

 to a different genus from any previously known, for which he proposes the name of 

 Bottosaurus} 



» Proc. Acad. Nat. Sci. Phila. IV, 169. 



