HANSEN : THE ISOPODA. 121 



Cymothoidse. The posterior portion of the lateral part of the segments men- 

 tioned is more or less protruding, rounded or angular, and must be considered 

 as the posterior division of the pleural plate (compare Cryptione). On the 

 three posterior segments the pleural plates are deeply incised, divided into a 

 larger, broader, and more produced anterior part, and a much smaller, nar- 

 rowei', and less produced posterior one, which is more or less obsolete on the 

 last segment. At least on the posterior segments the ventral side shows the 

 usual low fleshy keels. The legs are slender ; the second joint proximally on 

 the outer side with a considerable rounded expansion, which is comparatively 

 longer and broader on the anterior (Fig. 1 d) than on the posterior (Fig. 1 e) 

 pairs ; the other joints are normal. In Figure Id is shown the first leg with 

 its unusually large marsupial plate ; the transverse furrow is not deep ; on 

 the upper side the keel is tolerably high and much compressed, but without 

 marginal processes. The marsupial plates do not quite reach each other at the 

 middle ; their natural position was somewhat disturbed in the specimen, and 

 therefore it was necessary to make use of construction in Figure 1 a. 



Abdomen. The segments distinctly separated at the middle on the flat dorsal 

 surface. No pleural plates. The segments fleshy on the ventral side ; only 

 the fir.st segment with slight furrows. The pleopods very curious, and rather 

 similar to each other ; each consists of two rami ; the outer ramus is a very 

 long, subrectangular or distally rounded, somewhat fleshy lamella, which is 

 placed at the margin of the segment ; the inner ramus is. proportionally short, 

 more or less ovate, fleshy, originating at some distance from the outer ramus, 

 and on the left side of the animal it conveys the impression that the basal half 

 is fused with the ventral side of the segment. (I am aware that another 

 interpretation of the described facts could be advanced, namely, that the outer 

 ramus is a pleural plate set off by a kind of articulation, and that the inner 

 ramus in reality represents the entire pleopod, but this opinion I cannot share.) 

 Each uropod consists of a single lamella of about the same shape and size as 

 the nearest outer ramus of a pleopod. 



Size. The specimen is 8.5 mm. long to the apex of the abdomen, 10.3 mm. 

 long to the end of the uropods, and 7.2 mm. broad. 



b. Male. 



The shape of the body is interesting. It increases uniformly but rather 

 slightly in breadth from the head to the last thoracic segment, and the abdomen 

 is anteriorly somewhat broader than the preceding segment, triangular with 

 rounded angles, somewhat broader than long, the anterior margin a little con- 

 cave and the lateral margins convex. The body is a little more than 2^ times 

 longer than the width of the abdomen. 



Head. The dorsal surface is convex, the median part of the anterior outline 

 almost straight. A pair of small spots or minute depressions perhaps represent 

 the eyes. When the head is seen from below (Fig. lg),it is observed that the 

 frontal border arises like a broad and rather high transverse keel above the 

 attachment of antennulae and antennae. The antennulse of medium length, 



