CRUSTACEA. 173 



bears a caudal plate, telson and one of the eercopods. The plate is sub- 

 triangular, the telson moderately long but shorter than the cercopod ; all 

 are strongly carinate, and the surface covered with indications of strong 

 tubercles. 



Dimensions. The carapace of this species measures 28 mm. in length and 

 16 mm. in width across one valve. The telson is 28 mm. in length to the 

 extremity of the spine, and the cercopod has about the same length. 



Distribution. But a single individual of this species has been observed, and 

 this has been so flattened that some of its surface-features may be obscured. 

 The original is from the lower beds of the Portage group as originally defined 

 (the " Naples beds " of Clarke). Hatch Hill, Naples, Ontario county. 



EcHIXOCARIS CO.XDYLEPIS, 11. sp. 



PI. ATK XXIX, FIGS 11-17. 



Cephalothorax small, sub-ovate in outline; length to width upon each valve 

 as 3 to 2 ; greatest width centrally. Surface depressed. Hinge-line straight, 

 two-thirds as long as the carapace. Anterior margin gaping for a short dis- 

 tance on the dorsal line, abruptly angled at the anterior extremity and 

 rounding in a regular curve to the ventral margin and posterior extremity; 

 at the latter point the margin is broadly angulated and passes thence ob- 

 liquely forward in a nearly straight line to the hinge. The entire margin is 

 moderately broad and thick and strongly elevated, especially upon the 

 postero-dorsal edge. 



Nuchal furrow obscure. 



Cephalic region sub-triangular on each valve ; occupied by an irregular 

 node, which is distinctly limited on its anterior margin by a sulcus strongly 

 impressed near the hinge-line. This node bears four tubercles, which are 

 placed at the angles of a square, two close upon the hinge-line and two 

 situated ventrally. Of these the posterior ventral tubercle holds the posi- 

 tion of the optic node in Echinocaris punctata. 



