214 NEW YORK STATE MUSEUM 



reticulated striae. Near the ^pex the shell is furnished with a trans- 

 verse septum. 



Conularia niagarensis Hall (Fig. 145) (1852. Pal. N. Y. 2:294, 



pi. 65) 



Distinguishing characters. Broad, pyramidal, tapering abruptly; 

 deep abrupt channels of the angles; shallow, scarcely defined de- 

 pression of centers of faces; fine and closely arranged transverse 

 striae, which extend from the angles obliquely to the center, and 



-^ 



\ ■ .J- 



Fig. 145 Couularia niagarensis with several striae enlarged 



bend more abruptly in crossing the central depression; granulate 

 character of striae ; intermediate spaces with longitudinal striae. 



Found in the Rochester shale at Lockport (Hall). Probably 

 occurs also at Niagara. 



Class CEPHALOPODA Cuvier 



The cephalopods are the most highly developed mollusks, possess- 

 ing a distinct, well defined head, a circle of eight or more arms sur- 

 rounding the mouth and generally furnished with suckers or hooks, 

 a funnel-like hypononie, or swimming organ, and a highly developed 

 nervous system. The majority of modern genera are naked, or with 

 only a rudimentary internal shell (squids, cuttlefish, etc.). Nauti- 

 lus is the only modern genus with a typical external shell. 



The shells of cephalopods are chambered, i. e. divided, by a series 

 of transverse floors or septa, into air chambers. The last or living 



I 



