9 o 



NEW YORK STATE MUSEUM 



Cyrtoceras bovinum sp. nov. 



Plate 16, fig. 8, 9 ; plate 18, fig. 5, 6 



Large, robust, rapidly tapering, gently and regularly curved cones. In 

 the most complete the arc of outer curvature is 165 mm long and its chord 

 135 mm, the inner curve 115 mm long, its chord 98 mm. Section trans- 

 versely oval, more rounded in the apical parts, but very broad and flattened 

 and even slightly depressed medially on the venter. 



Septa closely arranged, from 2.5 to 4.5 mm apart; gently concave; 

 suture transverse with a low median backward turn or lobe on the venter. 

 Siphuncle subventran, moderately large, slightly contracted at the septa. 

 Living chamber long, not constricted as far as the specimens indicate. 



Surface covered with only fine, concentric growth lines, which combine 

 to form low bands or festoons. All the internal casts of this species bear a 

 highly characteristic roughened surface, caused by the excoriation of the 

 inner shell layers indicating a thick shell. All surface lines make a broad 

 backward curve on the venter but are apparently transverse on the dorsum. 

 The shell is traversed longitudinally by very faint, fine and unequal, some- 

 what undulating lines and grooves. These, however, are shown only on 

 two fragments which seem to have somewhat less curvature than the others. 



This species is represented by six or seven specimens from the Guelph 

 at Rochester, which show that it is by much the largest cephalopod in the 

 fauna at that locality. As a species it seems distinct from any that have 

 been described, in size, cross section and breadth of venter as well as in 

 surface characters. 



CTRTOBHIZOCEBAS Hyatt. 1 9OO 



Cyrtorhizoceras curvicameratum sp. nov. 



Plate 17, fig. 1-10 



Diagnosis. Conch a cyrtoceracone of moderate size, gently arcuate, 

 curvature of apical part not known ; expanding slowly, adult living cham- 

 ber having a length of 35 mm, widening from a basal diameter 0/37 mm 

 to an apertural diameter of 45 mm. Camerae very shallow, the sutures 



