440 K T. NEWTON ON A NEW PISH PROM 



with this definition of the latter genus; but then, although the 

 crowns of the teeth are compressed and the edges sharp and knife- 

 like, yet they are not so much flattened as they appear to be in 

 Daptinus ; and, moreover, the teeth in some species of Ichthyodectes 

 seem to make an approach towards this form. So far then as the 

 teeth are concerned, our specimen might be taken as an intermediate 

 form, and could be placed with equal propriety in either of these 

 two genera. With regard to the form of the mandible this specimen 

 differs from all the known species of Portheus and Ichthyodectes in 

 that it is longer in proportion to its depth, and has a shallower 

 symphysis. There is no groove near the lower margin as in some 

 species of Portheus and Ichthyodectes. The inner side of the alveolar 

 margin cannot be seen ; and therefore it is doubtful whether or not 

 there are foramina, such as are said to characterize the type speci- 

 mens of Saurodon and Saurocep7iahts. Another peculiarity of this 

 specimen is, that while the lower jaw is more elongated than in 

 Portheus and Ichthyodectes, the maxilla is shorter and deeper. 



The portion of the mandible of Daptinus figured by Prof. Cope does 

 not enable one to judge of its perfect form ; but in the description of 

 the species the jaws are said to be " long and slender ;" and in this 

 respect they resemble our specimen. The form of the skull gives us 

 no help in the generic determination ; for while the front part agrees 

 very well with the corresponding region of Daptinus as described 

 and figured (Cope, I. c. p. 214, pi. 47), its hinder parts answer 

 equally well to the description of the same region in Ichthyodectes 

 multidentatus (p. 212). 



Of the parts which we possess for comparison the jaws appear to 

 be the most characteristic ; and as in the form of its mandible our 

 specimen differs more from any known species of Ichthyodectes than 

 do the species of this genus from the species of Portheus, we are 

 justified in regarding it as belonging to another genus. And, further, 

 as it seems to agree with what is known of Daptinus, except in 

 minor points, which may be only of specific importance, it will, 

 perhaps, be best to place it provisionally in this genus. 



Dapyiinus pMehotomus is the only species of the genus at present 

 known; and the specimen described below 1 differs from that in 

 having the teeth longer in proportion to their width, and appa- 

 rently not so much compressed, while the prsemaxilla has only five 

 alveoli, there being, at fewest, nine in D. phlebotomus. The inter- 

 mediate position which our specimen occupies, more especially as 

 regards the flattening of the teeth, between Ichthyodectes and the 

 type of Daptinus, induces me to propose for it the name of Daptinus 

 intermedius. 



Daptinus intePvMedius, new species. (Plate XIX.) 



Mandible. — The most striking difference between this mandible 

 and those of Portheus and Ichthyodectes is the proportional shallow- 

 ness of its symphysis, and its more elongated form. Its greatest 



