454 Mr. George Sim on Diastylis bimarglnatus. 



gin is anteriorly produced to a broad obtuse point, and, when 

 vieived dorsally, is seen to turn outwards, and is fringed with 

 stiff hairs, which fringe extends along the antennal notch, 

 around the rostral projection, and along the lateral margin for 

 the first third of its length. A second ridge commences at the 

 dorsal aspect, and considerably behind the base of the rostrum, 

 continuing along the lateral to the posterior extremity of the 

 carapace, where it joins the infero-lateral margin. Along the 

 whole length of this second ridge it is cut into at regular inter- 

 vals, leaving a comb-like edge of broad flat teeth. In front of 

 and along the loxoer side of this ridge is a deep holloio, tohich 

 makes the comb-like process stand out in bold relief The 

 whole of the carapace is thickly set with short hairs. Five 

 somites of the pereion are exposed behind the carapace, all of 

 nearly the same depth, but longer as they succeed each other 

 posteriorly, the last having its latero-posterior angles pro- 

 duced to long sharp points, extending the whole length of the 

 first somite of the pleon. The first five somites of the pleon 

 are dorsally crowned with stout bent spines, becoming less on 

 eacli succeeding somite. The first four somites of the pleon 

 have their posterior angles rounded', but the post-inferior angles 

 of each are produced to sharp spine-like points. The fourth 

 somite has several spines on the lateral margin. The fifth 

 somite is longer than the four preceding, its upper posterior 

 margin being produced to an obtuse point ; there are four short 

 stout teeth on the dorsal aspect, several small spines on the 

 lateral margin ; and it is armed at the posterior extremity 

 with one strong tooth. The sixth somite is irregularly cylin- 

 driccd, having no sp)ines but one on the lower surface. The 

 telson is long, sharp, and styliform, and set on each side with 

 short stout sp)ines, increasing in size posteriorly. The styli- 

 form uropoda have the first joint about a sixth longer than the 

 telson, and supporting two branches, of which the outer is 

 about a third longer than the inner; and all are fringed with 

 hairs. The peduncles of the first pair of antennse are fully as 

 long again as the rostrum. In the second antennse the first 

 and second joints of the peduncle do not extend beyond the 

 rostrum, and the third joint, which is broad at the posterior 

 extremity, tapers gradually forward, and is set with short 

 spines on its inner edge ; it extends somewhat beyond the 

 extremity of the first pair of antennas. The filiform appen- 

 dage extends nearly the whole length of the animal. 



The fragments of legs figured are all that remained when 

 the animal was found. 



