DICHELASPIS LOWEI. 129 



Terga broad, with a deep notch corresponding to the 

 apex of the occludent segment of the scuta; the part 

 beneath the notch is of nearly the same width throughout, 

 and is twice as broad as the occludent segment of the 

 scuta ; it has its basal angle very broad and blunt. The 

 entire length of the terga equals two thirds of that of the 

 occludent segment of the scuta ; occludent margin simply 

 and slightly curved. 



The Carina is of nearly the same width throughout, 

 with the upper part rather the widest, and the apex 

 blunt; within convex; it extends up between three fourths 

 of the length of the terga, terminating downwards in a 

 fork with very sharp prongs, standing at right-angles to 

 each other (fig. 8 a.) The fork, measured from point to 

 point, is thrice as wide as, and measured across at the 

 bottom of the prongs it is wider than, the widest upper 

 part of the valve, — a resemblance being thus shown with 

 the triangular notched disc in D. Grayii. The points 

 of the prong extend under about one fourth of the length 

 of the basal segments of the scuta. 



Peduncle rather longer than the capitulum, which, in 

 the largest specimen, was ^ths of an inch in length ; 

 peduncle narrow, close under the capitulum ; membrane 

 thin and structureless. The larger specimen had almost 

 mature ova in the lamellae. 



Mouth. — Labrum with a few bead-like teeth on the 

 crest, distant from each other even in the central part ; 

 palpi rather small, moderately clothed with bristles. 



Mandibles, with four teeth; the inferior angle blunt 

 and broad, showing, apparently, a rudiment of a fifth 

 tooth ; the first tooth is as far from the second, as is this 

 from the inferior angle ; second, third, and fourth teeth 

 very blunt, whole inferior part of mandible not much nar- 

 rowed. Maxillae small, with a small notch under the 

 three upper spines, which are followed by five or six pair, 

 nearly as large as the upper spines. 



Cirri. — First pair remote from the second ; their rami 

 nearly equal, and about one third of the length of the 



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