﻿O SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 59 



lower jaw, it appears that the sulcus alveolaris, — the furrow in the 

 upper border of the mandible in which the embryonic rudimentary 

 teeth are lodged (which ordinarily disappears in adult finback 

 whales),* — fills up almost entirely with bony tissue; that the cannabis 

 mandibularis, — the canal in the interior of the jaw, in which the third 

 branch of the nervus trigeminus and the accompanying blood-vessels 

 run, — is divided into an upper and a lower branch, while, as a rule, it 

 is undivided. From the upper branch'. — Cope's ' alveolar groove/ 

 sulcus alveolaris — proceed, on each border, foramina mentalia, which 

 are simply orifices of side branches from the canalis mandibularis. 



" As regards the second objection, the mandible in Cetotherium 

 shows in section an entirely similar figure to Cope's Siphonocetus. 

 Brandt figures it in the type of the genus, C. rathkei. On the score 

 of the canals of the lower jaw, there was no ground for establishing 

 a new genus. Siphonocetus is, therefore, much in need of new 

 proofs." {Op. cit.jp. 25.) 



Ulias Cope. — " The characters of the genus are that the canalis 

 mandibularis and sulcus alveolaris are not separated, and together 

 form a broad, wide-open canal in the upper border of the mandible, 

 which may, however, be closed near the anterior end of the jaw ; and 

 that the foramina mentalia are wanting, except at the very front. 

 Cope believed that Ulias, when adult, retained characters which are 

 found elsewhere in embryonic Right whales. But Cope's interpre- 

 tation is certainly not correct. The lack of the foramina mentalia 

 alone is so extraordinary that it gives grounds for questioning 

 whether the upper border of the jaw in the specimen concerned is 

 really undamaged. From the figure, which represents a diagram- 

 matic section, one gets an impression of the jaw that is very far from 

 reminding one of an embryo of a Right whale ; that it is as in the 

 fully grown Finbacks, but that the upper border is broken off, so that 

 the bottom of the canalis mandibularis has become visible. This 

 explanation is, however, a guess, but it may be right, nevertheless. 

 It should also be remembered that it is very difficult in a weathered 

 bone to distinguish broken surfaces from natural surfaces. In order 

 that the genus Ulias may be accepted, there must be presented a far 

 more carefully prepared account of it than that which Cope has 

 given." {Op. cit., pp. 26-27.) 



Tretulias Cope. — " Tretulias was established by Cope from two 

 pieces of the lower jaw from the North American Miocene, one 

 piece ' in fairly good preservation,' the other ' considerably worn.' 

 The single species is T. buccatus. The characters of the genus are 

 that the canalis mandibularis is ' obliterated ' and that the sulcus 

 alveolaris is open, without a bony roof, except along the inner bor- 

 der, where there are found ' gingival canals and foramina.' Cope's 

 interpretation cannot be correct. That the canalis mandibularis 

 should be ' obliterated ' is inconceivable. What he calls the ' dental 

 groove ' — sulcus alveolaris — is clearly enough the canalis mandibu- 

 laris, to judge from the figure, a diagrammatic section of the jaw. As 

 in Ulias, it is sure that a piece of the upper border of the jaw is broken 



