126 



SHIGEMl ISHII. 



the sac, which position probably stands in relation with the facility of 

 respiration by means of the pleopocls. In the living state, the plcopods are 

 visible in constant motion near the orifice. 



Adult female (fig. i). — Ccphalon some- 

 what triangular in outline, a little wider 

 than long ; anterior end rounded, or more or 

 less truncated. Antennule and antenna 

 (fig. 2) short, the former being slightly longer 

 and a little stouter than the latter. Both are 

 usually eight-jointed. In the antenna, the 

 second proximal joints short and thick ; the 

 third and fourth larger and of about equal 

 size ; the seventh and eighth, especially the 

 latter, are small. In the antennule, each 

 joint is a little broader than long, except the 

 last one which is slightly longer than broad. 

 Antennule somewhat flattened antero- 

 posteriorly ; 1.07 mm. long and 0.23 mm. 

 broad in the middle. Antenna 0.9S mm. long and 0.14 mm. broad in the 

 middle. 



Eyes approximately oval ; anterior inner 

 end slightly concave or nearly straight, 

 posterior end rounded ; those of females 

 generally appreciably smaller than those of 

 males (longest diameter : 0.53-75 mm. in § ; 

 0.77-94 mm. in ^). 



Of the seven mesosome segments, the first 

 is the longest ; the second and third nearly 

 equal with each other, but somewhat shorter than the first ; the remaining 

 four, especially the last, arc markedly shorter than any preceding ones. 

 Mesosome not widened to a pronounced degree, as it is in /. japonensis ; 

 hence, the breadth of body remains nearly the same for the most part. 



F ig. I. 



l.opistìiopteryghtm, n. sp., 

 Magn. about 5X. 



Fig. 2. 



Antennule (a) and antenna (b) of £. 

 Magn. about 24 X. 



