352 DE. W. T. CALMAN OX jSEW OE EAEE 



Nannastacus leptukus, sp. n. (Plate XXXIII. figs. 1-3.) 



Lescription of adult Male. — Total length 2-0 mm. 



Carapace a little more than one-third of total length, slightly compressed, dorsal 

 margin slightly arched. The pseudorostrum, seen from the side, is short and trnncate. 

 Antero-lateral margin concave, forming a widely open antennal notch ; antero-lateral 

 angle rounded, hardly produced. Eyes prominent, darkly pigmented, set rather close 

 together, the distance between them not more than one-eighth of the length of the 

 carapace. 



The first leg-bearing somite is distinct. The pleural plates of the succeeding thoracic 

 somites are hardly expanded laterally. 



The abdomen is nearly equal to the cephalothoracic region. The somites are 

 cylindrical, each with a well-marked lateral groove ; the fifth somite is one and a 

 half times as long as the fourth and twice as long as the last, which is truncate 

 posteriorly. 



The peduncle of the antennule has the three segments (as seen without dissection) 

 subequal, the second with a short distal process on the upper side, not reaching beyond 

 the end of the segment ; both fiagella have two segments, and the inner flagellum is a 

 little shorter than the first segment of the outer. 



The first legs have a slender dactylus, about two-thirds as long as the propodus. 



In the last pair of legs the basis is little more than one-third of the length of the 

 limb, the carpus is less than twice as long as the merus, and one-third longer than the 

 propodus, which again is about equal to the dactylus with its claw. 



The peduncle of the uropods is more than twice as long as the last somite, slender, 



wdth five spinules on the finely serrated inner edge. The endopod is about half as long 



as the peduncle, with a terminal spine of less than half its length and seven spines, 



increasing in length distally, on the inner edge. The exopod is about four-fifths of 



xie length of the endopod and bears a slender terminal spine of its own length. 



Bemarks. — N. longirostris G. O. Sars, N. Iraclnjdactylus Caiman, and the species 

 described above form a group defined from the other species of the genus by having 

 the peduncle of the uropods at least twice as long as the last somite. X. Mrsutus 

 Hansen, which has the peduncle only about equal to the last somite, agrees witii the 

 first two of these species in the length of the pseudorostrum, of which the lateral 

 plates meet above for at least one-sixth of the total length of tlie carapace. From all 

 these species If. lepturus is distinguished by the very short pseudorostrum and by having 

 the abdomen nearly equal to the cephalothoracic region. 



Occurrence. — "Suez, 3/1/98, H. Mortensen."' Copenhagen Museum. 



Nannastacus zimmeki, sp. n. (Plate XXXIII. figs. 4-15.) 



Description of adult Female. — Total length 1-5 mm. 



Carapace a little more than one-third of total length, inflated behind, where the 



