54 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 76 



rostrum until the infraorbital foramen is brought to a position behind 

 the orbit and wholly bgneath the greatly elongated optic canal ; 

 the formation of the anterior orifice of the infraorbital canal by the 

 pterygoid, frontal, and maxillary to the exclusion of the palatine and 

 lacrimal. 



Genera zvhose position is not clear. — Several extinct genera which 

 have been carefully described so far as the known material would 

 allow are still too incompletely understood to be assigned to a 

 definite place in the present classification. Some of these have already 

 been mentioned / see especially remarks on the Agoropliiidcc, PhySc- 

 tcridce, Iniidce, Dclphinince, EurliinodelpJiinincc and Stenodclphinincc) . 

 Others whose position is still more doubtful are those which have 

 been described under the names Cyrtodclphis, Diochoticns, Eoplata- 

 nista, and Squalodelpliis; also a remarkably long-beaked dolphin from 

 the Calvert formation of ^laryland. an account of which, by 

 Mr. Remington Kellogg, is now in press. 



