302 AiirniroDA norm alia, 



slightly cun-cd : the third pair of pcreiopoda arc not longer than 

 the preceding, but have the inferior distal angle produced to a sharp 

 process reaching to about one-third the length of the propodos ; 

 the propodos is longer than the carpus, having the inferior margin 

 hollowed, therefore presenting two margins, each of which is pro- 

 duced anteriorly to a sharp point, between which the dactylos falls 

 in closing on the propodos ; dactylos terminating in a hook-shaped 

 sharp unguis : the fourth pair of pereiopoda resemble the pre- 

 ceding, except in being slightly longer ; the carpus has the infe- 

 rior angle considerably more produced and more slender, waved 

 also ; the propodos is long and narrow ; tlie dactylos, which closes 

 between the teeth-lilve process at the inferior extremity of the 

 propodos, terminates in a hook-shaped unguis : the fifth pair are 

 not very distinct at their junction with the body, they are short, 

 reaching to about half the length of the preceding, having the joints 

 subequal, terminating obtusely, and furnished with a subapical 

 spinule and spine tipped with a rudimentaiy unguis : this spine 

 probably corresponds with the inferior distal carpal process of the 

 two preceding pairs of pereiopoda, the propodos being imperfectly 

 developed and the dactylos absent. Only two, or at most three, pairs 

 of pleopoda are developed (and these in a very rudimentaiy stage), 

 consisting of a peduncle and two terminal processes, the rudiments 

 of the future rami. The telson is very large, being nearly as broad 

 as the rest of the posterior portion of the animal, and terminating 

 round and smooth. 



The following are points of interest:— The superior pair of antennae 

 assume a more developed condition in the larva than in the adult, 

 while the converse is the case with the inferior pair. The gnatho- 

 poda are almost embryonic, exhibiting no trace of their future im- 

 portant character. The first two paii-s of pereiopoda bear no incon- 

 siderable resemblance to those of the adult animal ; whilst the two 

 next vary from the type in the adult altogether, assuming a form 

 that corresponds more nearly with those of Phronhna. 



2. Vibilia affinis. (Plate XLIX. fig. 8.) 



Vibilia affinis, MS. Cat. Musee Jardin des Plantes. 



Cephalon as long as deep. Eyes small. Superior antennoD longer than 



the cephalon ; peduncle about half the length of the cephalon, first 



joint as long as the two succeeding joints ; flageUum three times as 



long as the peduncle, lanceolate, acute. Inferior antennre slender, 



not longer than the siiperior, reaching to about the third segment 



■ of the pereion. Gnathopoda short, small, slender ; second pair 



having the carpus inferiorly produced. First two pairs of pereio- 



