304 TRANSACTIONS OF THE [mAR. 15, 



the fish it belonged to, though one of the Dinichthyidae could 

 hardly have belonged to the type genus. The dentary bone, the 

 only portion yet known, turns up at the end to form a strong 

 tooth as in Dinichthys and this tooth interlocked with a sheathing 

 premaxillary by which its extremity is much worn. In Dinich- 

 thys, behind the prominent anterior tooth is a second and lower 

 one which terminates below in a ridge that crosses the inner face 

 of the dentary bone. In the jaw before us no such tooth or in- 

 ternal ridge is found, and it is evident that this characteristic of 

 Dinichthys is wanting. The posterior extremity of the dentary 

 bone in Dinichthys is flattened and spatulate, was once buried in 

 cartilage, and is longer than the exposed portion of the jaw. In 

 the fossil before us, however, no such spatulate extremity has 

 ever been present. The exposed portion of the jaw is narrowed 

 behind and thinned to a wedge-shaped point ; it was also appar- 

 ently cleft vertically and thus spliced on to the cartilaginous 

 posterior portion, the size and form of which we have no means 

 of knowing. The figures now given of the inner and outer 

 aspects of the jaw of Stenognathus will supplement the verbal 

 description and give a clear idea of its character. 



As the two left dentary bones are the only remains yet known 

 of this fish, it is apparent we have yet much to learn in regard 

 to its structure. Possibly other parts have been made known 

 to the public under other names. In the same localities and 

 strata where these jaws were found a number of highly orna- 

 mented dermal plates have been obtained by Mr. Terrell and to 

 these I have given the name of Glyptaspis. It is possible that 

 the jaws of Stenognathus formed parts of the same fish, but of 

 this there is no evidence and no indication except the want of 

 jaws for Glyptaspis. Other jaws, however, are found in the 

 same formation — those described as Mylostoma — which have not 

 yet been associated with any cranial bones, and these are better 

 proportioned in size to the plates of Glyptaspis. 



Stated Meeting. 

 March 22d, 1897. 

 The Academy met with President Stevenson in the chair. 

 The minutes of the last meeting were read and approved. 



The following papers were read by title : " The Serpentines 

 near New York City," by D. H. Newland. " The Trenton Strata 

 in the Valley of Lake Champlain," by T. G. White. The publica- 

 tion of these papers was unavoidably postponad to a later volume. 



