PLATYSCELID.K. 333 



monts two, not large. Tnfonor antenna) slentl(>r, straiglit, fonr- 

 jdintcd, first joint longest, Hceond and third about ecinal, f'ourtli 

 shortest. Bases of third pair of peroiojioda witli a very oljliqne 

 truncation at extremity, apex acute ; posterior margin arcuate : 

 [basos] of fourth pair twice as large [as that of the third], obtuse 

 at apex, ovato-lunatc ; posterior margin arcuate throughout, an- 

 terior margin equally excavate : [basos] of seventh pair small and 

 slender, subcnsilbrm. Telson triangular, sidi;s towards apex ob- 

 solctely excavate, apex subacute. Posteiior pair of pleopoda arti- 

 culated with under surface of segment ; rami very unequal, not 

 longer than base. 

 " Length, when closed up, 4 lines ; when extended, about 6 lines, 



'* Hah. Taken from the stomach of a Eonito caught off the 

 Canaries, September 1838." — Dana. 



4. BRACHYSCELUS*, n.g. 



Cephalon rounded in front. Pereion not broader than the cephalon. 

 Pleon a little narrower than the pereion, having the fifth segment 

 wanting, or fused with the fourth. Eyes large, encroaching on 

 the inferior surface of the cephalon. Antennae obsolete or very 

 rudimentarj'. Gnathopoda complexly subchelate. Pereiopoda 

 short : first two pairs small, slender, not dilated ; third pair 

 having the basos large, articulating with the ischium at the 

 apex ; foiu'th pair not longer than the thii'd, basos rather larger 

 than that of the third, articulating with the ischium at the apex ; 

 fifth pair a little shorter than the fourth, basos rather smaller 

 than that of the fourth and articulating with the ischium at the 

 apex, the other joints developed. Posterior pair of pleopoda bira- 

 mous, foliaceous. Telson as broad at the base as the preceding 

 segment of the pleon. 



This genus diff'ers from Pronoe. TJu/ropus, and JVdfifac f J us in luiving 

 the fifth pair of pereio2)oda fully developed, and in having the an- 

 tennae obsolete. It also differs from the two latter in having the basa 

 of tlio tliird and fourth pairs of pereiopoda not so largely developed, 

 and in the animal generally being more compressed. 



1. Brachyscelus cruscuhim, n. s. (Plate LIII. figs. 2 & 3.) 



Female. — Cephalon laterally semi-hemispherical, rounded in front. 

 Eyos large, inferiorly developed, and encroaching upon the inferior 

 surface. Antenna; obsolete. First pair of gnatliojjoda shoil. having 

 the carpus very large, broader than long, the inferior angle anteriorly 



* /3(oaxt's. sliort ; oKtKoi, leg. 



