,, the imen is more distincl tlian in the smaller. The carinal margin 



the tergal margin; where these margins meel an obtuse angle is 



.1 ii"t ver) prominenl ridge runs to the occludent margin. This 



the outer surface <>i' the scutum. Internally ;i m <i ver) prominent ridge 



ver half of the occludent margin, whereas ;t much more prominent and bowed 



imall basal portion from the rest of the valve. Where these t\\i> ridges meet, 



ludent margin, .1 relatively strong tooth having the shape of a linie nail, is formed. 



rergum fig, i and ;,/' triangular, relatively small. Carinal margin and scutal margin 



iame Iength; the former does not show the flattened border which is so 



for 1/ striatum. 



fig. 2, ie and .) broad towards its basal end, much bowed, terminating 

 in a narrow fiat part which runs up to the basal ends of the terga. The flattened 

 il margin is narrow and has about the same breadth throughout its Iength. The lias.- is 

 abruptly truncated. The scutal margin at one third of its Iength from the base shows a smal! 

 tooth or exi ce which fits into an indistinct excavation in the carinal margin of the scutum. 



This detail of the structure seems more stronglj developed in younger specimens it cannot 

 at any rate be made out so sharply in full-grown specimens without isolating the val. 

 Peduncle very short, slightly extending from underneath the capitulum. 

 Size. The largest specimen has a capitulum of ï cm. in Iength. 



Mouth. Labrum (fig. 5) bullate; crest with a row of numerous : ' 40) small triangular 

 . 1'alps small. hairs numerous at the tip and along the interior margin. 



Mandibles fig. 6 with tour teeth, the interior angle terminating in a single delicate 

 spine. The distance between the tips of the first and second teeth one and a half times as 

 great as that between the tips of the second and third. 



Maxi 11 ae (fig. 7 with three spines at the upper angle, the notch beneath the upper 

 spines relatively large and the inferior raised part rather narrow. There are three delicate hairs 

 or spines planted in the notch, and about ten larger ones on the part beneath the notch. 



Outer maxillae of a quadrangular shape with rounded edges. Numerous, delicate 

 hairs planted on the outer surface, the largest along the outer margin. 



1 irri. First pair t'ar removed from the second pair with very short rami. Rami not SO 

 much differing in thickness, much more so in Iength. The longest ramus has ten, the shortest 

 nine segments. Spines planted over a great part of the surface of each segment. The second 

 cirrus has about the same shape and structure as those following : each ramus consists of long 

 and narrow segments; two stronger and a third much more delicate spine are planted at the 

 convex side near the extremity of each segment; the concave side having as a rule three 

 stronger pairs of spines and a fourth very delicate pair. An extremely delicate spine is inserted 

 in the angle formed by each pair of stronger spines. 



tudal appendages fig. 8). Very short, terminating abruptly and broad, and 

 • very large number of fairly strong hairs at its truncated extremity. 

 Penis in the specimen that was dissected broken off; the part attached to the body 

 cylindrical with hairs here and there. 



32 



