8S4 



FAUNA ANTIQUA SIVALENSIS. 



an irregular ovate form, and has the same obliquely trans- 

 verse direction as in the Otter. The surface is so flat and 

 sinuous that it is di£B.ciilt to recognize its constituent 

 elements ; but it is divided, as in Lutra, by a shallow 

 furrow ; the outer portion consisting, as in the latter, of two 

 unequal tubercles ; the inner, which is much larger, is 

 elevated into three obtuse tubercles, arranged in a triangle, 

 and surrounded by a blunt ridge. 



In the lower jaw the tubercular is comparatively small, as 

 in the Otter. It is oblong across, and umbUicated, with four 

 indistinct surfaces suiTOunding the depression. The car- 

 nassier is of a broad ovate form; the flattened surface of 

 the crown being raised into four inequalities, representing 

 the three cusps and heel of the corresponding tooth in the 

 Otter. The false molars in both jaws are only remarkable 

 for their robust and obtuse form. 



These minutise may appear tedious, but we have found it 

 necessary to enter into them so much at large, as the den- 

 tition of the fossil genus occupies in certain respects a mean 

 position between that of Lutra and Enhydra. In deter- 

 mining fossil animals no assistance is derived from the soft 

 parts, or external characters ; the means for their identifica- 

 tion are often limited, as in the present instance, to an 

 isolated part of the skeleton; and the anatomist has it 

 forced upon him to go rigidly into the comparison of every 

 character, in order to be able to apply with any certainty the 

 laws which regulate correlative organization to the recon- 

 struction of the form, and the determination of its affinities. 



Now, in regard to the teeth of Enhydriodon. The speci- 

 mens, fortunately, supply information regarding all those of 

 the upper jaw, even to the deciduous precanine false molar. 

 The incisors (PI. XXVII. fig. 2) are of the normal number, 

 three on each side, the two interior of which are shown by 

 their transverse section to have been very compressed, their 

 length being three times their width. This compression, so 

 much greater than what is seen in either Lutra or Enhydra, 

 or in any other described Mustelida, is palpably connected with 

 the enormous development of the outer incisor on either 

 side, which relatively exceeds that of any known Carnivora. 

 This lateral incisor evidently served as a subsidiary canine,' 

 and the only analogous case which occurs to us is found in a 



' From this canine character of the 

 outer incisor, we were indvieed, in the 

 first instance, to name the genus 

 Amyxodon, or, par excellence, Lama- 

 rian, but subsequently adopted that of 

 Enhydriodon as significant of its affini- 

 ties, a useful consideration in naming 



fossil mammiferous genera. It is men- 

 tioned imder the name Amyxodon in a 

 catalogue of Sewalik fossils in the 

 Journalof the Asiatic Society of Bengal, 

 vol. iv., 1836, p. 707, and in Dr. Eoyle's 

 ' Illustrations of the Botany of the 

 Himalayahs,' vol. i. p. 31, 



