REPORT ON THE ISOPODA. 73 



are not given off at corresponding points. The anterior pairs are placed considerably 

 more dorsally than are either of the two hinder pairs. 



The abdominal shield is separated from the last segment of the thorax by what appears 

 to be two free abdominal segments. It should have been mentioned that the three 

 posterior thoracic segments are separated from each other by a thickened rim which is 

 conspicuous in the actual specimen by its white opaque colour. 



The abdominal shield is ridged along its anterior margin, and the interval which 

 separates it from the posterior ridge of the last segment of the thorax is itself divided 

 into two equal areas by a median ridge-like thickening ; this appears to be the boundary 

 between the free abdominal segments ; they are extremely narrow, their relative propor- 

 tion beino; shown in the figure. 



It is impossible to describe with accuracy the shape of the abdominal shield, as it is so 

 soft and impressionable ; the accompanying figure, however, is approximately correct ; the 

 termination of the abdominal shield is, as it were, bent underneath the body, so that the 

 anus comes to look almost forwards instead of downwards or backwards. The intestine 

 does not run straight to the anus but follows the convex outline of the caudal shield, 

 passing round by its greater curvature. 



It was very easy to ascertain the course of the alimentary canal without any dissec- 

 tion ;- the muscles of the species are so slightly developed that the body cavity appears 

 to be entirely empt3 r save for the presence of the gut, which was conspicuous through 

 being full of dark-coloured food. 



The anus is guarded by large flap-valves indicated in fig. 1 of PI. XIV. 



The appendages are only represented by the gnathopods and the abdominal limbs, 

 and by traces of the other appendages. 



One antennule is nearly perfect ; it consists of a stout basal joint giving off a strong 

 pointed process on the outer side, with this are articulated two other smaller cylindri- 

 cal joints, the third very considerably longer than the second ; the flagellum is broken 

 off at the tip and is evidently of some length ; the proximal region of the flagellum is not 

 ringed ; distally the flagellum is constricted into rings which are (fig. 5) extremely short. 



The antennas are only represented by four short basal joints. 



Both the antennas and the antennules of the specimen are directed more upwards 

 than is usually the case ; this is shown in the lateral view of the entire Crustacean 

 (fig. 1). The insertion of the antennas is also rather in front of that of the antennules. 



The mandibles are stout and powerful and have no trace of a palp. 



In the Jirst pair maxiUse the upper lobe has the usual form and is provided along its 

 anterior edge with numerous firm, yellowish spines, among which are abundant fine hairs ; 

 the lower lobe is densely beset with hairs but has no spines ; its extremity is rather pointed. 



The second pair of maxillse is very closely similar to the same pair of appendages 

 in Eurycope sarsii. 



(ZOOL. CHALL. EXP. — PART XL VIII. — 1886.) Bbb 10 



