to have a "marked longitudinal medio-dorsal depression". In the Siboga specimens these somites 

 are flattened on the dorsal surface but not distinctly hollowed. 



Occurrence. Stations 37 and 40. Plankton. Many specimens. 



Distribution. Samboangan, Philippine Islands, surface (Sars) ; Blanche Bay, New 

 Britain, surface (Stebbing). 



3. Nannastactis parcius n. sp. (Text-fig. 2, a — c). 



Description of adult Male. Total length 1,7 mm. 



Carapace one-third of total length, subcylindrical, dorsal surface slightly depressed between 

 the branchial regions. Pseudorostrum very short, upturned and rounded. Antero-lateral angle 

 rounded, projecting forwards to a level with the short pseudorostrum, armed with a single 

 curved tooth on its outer surface. The pseudorostral plates do not meet in front of the cephalic 

 lobe. The eyes are very large and darkly pigmented, each with three hemispherical corneal 

 lenses. The surface of the carapace is smooth, without tubercles or spines. 



Fig. 2. Nannastaciis parJiis n. sp., .idult male. 

 a. From the side, appendages omitted. /'. Fifth leg. c. Last somite and Uropod. 



The pleural plates of the free thoracic somites are expanded laterally and the somites 

 are unarmed and rounded on the dorsal surface. 



The abdomen is very stout, about equal in length to the cephalothoracic region. The 

 first four somites are about as broad as long and the first five have a well-marked lateral 

 groove. The terminal somite is but little shorter than the preceding, bluntly pointed posteriorly 

 and with the anterior margin thickened and everted, especially at the sides. The abdominal 

 somites, especially the last two, are beset on the dorsal surface with short setje. 



The antennules and the anterior legs do not difter materially in their proportions from 

 those of N'. ungtuctilatus but the posterior legs are relatively longer. The last pair (text-fig. 2 <5.) 

 are about two-fifths of the total length of the body and very slender. The carpus is about equal 

 in length to the basis and longer by one half than the propodus. The dactylus and its slender 

 curved claw are together a little shorter than the propodus. 



