26 Colorado College Studies. 



was made to include the type-genera of the families Sphyrse- 

 nidse, Mugilida? and Atherinidae. 



In studying the Cretaceous teleosts in the collection of 

 the University of Kansas, Mr. Alban Stewart* has recently 

 treated Sylliemus under the Mugilidte, but adds that its posi- 

 tion in that family is very doubtful. The present writer 

 believes that Sylhemus, though presenting relationships to 

 the Mugilida3, can not be referred to that family, and should 

 be made the type of a distinct family, SylUemidj^, diflPering 

 from the Mugilida3 and resembling the Sphymenid.'c in hav- 

 ing the body elongate and subcylindrical and the head long, 

 pointed and pike-like, and in the presence of a lateral line, 

 the latter extending along the middle of the sides; differing 

 from the Mugilidpe and resembling the Atherinidje in having 

 the vertebra:' considerably more than 24; differing from the 

 usual condition in the suborder Percesoces by the subin- 

 ferior position of the pectoral fins, and from that in the order 

 Acanthopteri by the relatively posterior abdominal position 

 of the ventrals, and apparently by having the anterior part 

 only of the mouth border formed by the premaxillary. 



Genus SYLL^MUS. 



Syllcemus Cope. Report U. S. Geological Survey of the Territories, 

 Vol. II, p. 180; 1875. Stewart, University Geological Survey of Kansas, 

 Vol. VI, p. 383. 



Type, Syllcemus latifrons Cope. 



Body subcylindrical or fusiform, not compressed; skull 

 depressed, flattish-convex above from right to left, broad 

 across the occipital region, in advance of which it is some- 

 what contracted and produced to form a bill-like muzzle, 

 tapering to a narrow, truncate extremity; cranial bones, for 

 the most part, of subtriangular outlines as seen from above, 

 those on the occipital region short, those of the muzzle elon- 

 gate; inferior side of head contracted, the coracoid bones 

 forming a keel and the lower borders of the dentaries and 

 also those of the large opercular bones meeting at the infero- 

 median line; mouth-cleft long, extending to two-thirds of the 



♦University Geological Survey of Kansas, Vol. VI, p. 38.3. 



