PLA'fYSCKLID.1'. 331 



of auditory t.ilia ; ilagellum short and narrow, consisting of one long 

 and one short torniinal articidus. Interior antenna; four-jointed ; 

 first joint longest : second about half the length of the first ; third 

 half longer than the second ; fourth narrower than the preceding, 

 as long as the second, terminating in a Itmceolatc joint. First pair 

 of gnathopoda ha\"ing the caiiiua antero-inferiorly produced nearly 

 to the extremity of the propodos, and serrated both inferiorly and 

 anteiiorly ; propodos long-ovate, and serrated both on the superior 

 and inferior margins ; dactylos short, sharp, and antagonizing with 

 the extremity of the carpus : second pair like the first, but longer, 

 narrower, and having the inferior angle of the cari)us produced 

 rather beyond the extremity of the propodos. First two pairs of 

 pcrciopoda having the mera stouter than the carpi, the carpi shorter 

 than the mera and minutely pectinated on the posterior margin ; 

 propoda slightly shorter than, and not so stout as, the carpi, mi- 

 nutely pectinated on the posterior margin. Third pair of pereio- 

 poda ha^"iug the distal portion of the anterior margin serrated, 

 and the ischium articulating subapically within the posterior 

 margin ; remaining joints about haK the length of the bases ; the 

 meros, carjjus, and propodos serrated on the flexible margin. 

 Fourth pair of pcreiopoda with the ischium articulated near the 

 centre, the remaining joints being not quite one-fourth the length 

 of the basos ; carpus and propodos serrated on the flexible margin. 

 Fifth pair of pereiopoda having the basos membranous, a small 

 round tubercle representing the remaining joints. The rest of 

 the animal appears to resemble Platyscelus Rissoince. 

 Length |-i^^^ ^^ '^^ inch. 



Uab. Locality unrecorded. Taken by M. Morrisse of Havre. 



The specimen from which this description and figui-e arc taken is 

 a female. 1 fortunately found witliin the iiicubatory punch nume- 

 rous larva;. These differ considerably in form from the fidly deve- 

 loped animal, as will be seen by the following description : — 



Young. — Cephalon long and narrow, tapering anteriorly, having the 

 apex reversed beneath. Pereion long, not dilated, nut deeper than 

 the cephalon. Ficon nearly as long as the pereion. Antenna? upon 

 the inferior surface : the superior paii', just within the anterior 

 margin, consist of two subequal joints, the basal one carrjing 

 distally two minute hairs ; the terminal one truncate, the distal 

 extremity carrpng four long hairs. Inferior antenna; posterior 

 to the superior, consisting of but a single joint, cylindrical in form, 

 truncate at the apex, where are situated four short hairs. First 

 pair of gnathopoda ha\ing the meros a little broader than the 

 caipus, and the antero-inferior angle lipped with a solitary hair; 



