exopods, and in having the basis of the third maxillipeds strongly produced. On these grounds 

 it is referred, provisionally, to the same genus. It differs considerably from H. Sarsi however 

 in the fact that the exopods of the second and third legs are well developed and hardly 

 smaller than that of the first leg, and also in the form of the merus and carpus of the third 

 maxilliped, the former being scarcely produced externally and the latter not broadened. 



The species takes a place among the largest known Cumacea. In length of body it appears 

 to be excelled only by the Arctic Diastylis goodsiri, which sometimes reaches a length of 35 mm. 



Bathycuma. 



I. Bathycuma longirosiris n. sp. Plate II, figs. 13 and 14. 



Description of immature Male. Total length 12 mm. 



Carapace a little more than one-fourth of the total length, compressed, its transverse 

 width little more than one third and its vertical height less than one half its length. The dorsal 

 edge is sharply keeled and moderately convex as seen from the side ; its anterior half is cut 

 into a double row of alternating teeth. The pseudorostrum is long, about one-fifth of the 

 length of the carapace, horizontal and acutely pointed. There is no eye and the ocular lobe is 

 represented by a narrow wedge-shaped process lying between the lateral plates of the pseudo- 

 ro.strum. The antero-lateral margin is deeply concave, forming a nearly semicircular antennal 

 notch. The antero-lateral angle is acute and just behind it the lower margin is obscurely serrated. 

 The posteror margin is vertical. The fourth leg-bearing somite has the pleural plates produced 

 anteriorly on each side into a narrow rounded lobe carrying a single seta. The abdomen is a 

 little over half the total length, rather stout, and quite smooth. The last somite has a large 

 supra-anal lobe, with a convex hinder margin. 



The antennules have last segment of the peduncle slightly swollen, the outer flagellum 

 composed of two segments of which the first is twice as long as the second, and the inner 

 flagellum very short, also two-segmented, with the second segment very minute. 



The mandibles (seen by transparency through the carapace) have a normally elongated 

 body, not abbreviated as in the Lciiconido'. 



The third maxillipeds have the basis produced distally in a large lobe which reaches to 

 the distal end of the merus and has a strongly serrated edge beset with long plumose sette. 

 There a few teeth distally on the lower surface of the basis. 



The first legs exceed by about one-third the length of the carapace. The basis is strongly 

 denticulated on its lower surface near the outer edge. The distal segments are very slender 

 the dactylus a little shorter than the propodus and longer than the carpus. 



The second legs have the ischium distinctly defined but very short; the distal segments 

 are armed with stout spines and the dactylus is long and slender. The exopod of the third 

 pair is equal in size to that of the second and a little smaller than that of the first pair. The 

 fourth pair of legs are sub-equal in length to the third pair but the exopod is little more than 

 half the size of that on the third pair and bears only a few very short seta: at the tip. The 

 last pair of legs are distinctly shorter than the preceding. 



SIBOGA-EXPEDITIE XXXVI. 2 



