726 THE VOYAGE OF H.M.S. CHALLENGER. 



which, at regular distances, are planted a series of solitary spinules, also present on 

 the same margin of the carpos and meros. The fourth pair of pereiopoda (fig. 3«) is 

 shorter than the third, and like it carries a long basecphysis, and terminates in a long, 

 curved dactylos that is fringed at the posterior margin with a series of spinules, and 

 furnished with a bundle of hairs at the base of the unguis ; the distal extremity of the 

 propodos is furnished with long spinules, and the posterior margin with distantly planted 

 solitary ones, all of which have their margins near the base fringed with short stiff cilia. 

 The fifth or posterior pair of pereiopoda (fig. 3o) is shorter than the fourth, and does 

 not, like the preceding pairs, carry any basecphysis ; it terminates in a short, stout, 

 biunguiculate dactylos, and is fringed on both sides with short hairs ; the proj)odos is 

 long, and gradually increases in breadth, the distal extremity being posteriorly excavate, 

 and the posterior angle armed with two long and stiff spines, between which the dactylos 

 impinges and forms an imperfect chela ; the posterior margin of the propodos is thickly 

 fringed with a series of short inversely curved spinules, fringed at the posterior margins 

 only near the extremity with short hairs, and at the distal extremity of the anterior 

 margin with a series of long hairs that are fringed with pointed cilia. 



The pleopoda are all unequally biramose; the anterior two pairs appear to be the more 

 robust, although all have strong peduncles. The sixth pair has the rami unequal, the 

 inner being lanceolate and fringed with hairs, all of which are rubbed off, and the outer 

 is furnished with a small tooth which stands at the extremity of the diaeresis, and the 

 distal and inner margins are fringed with hairs which are lost in our specimen, but the 

 points of articulation are conspicuous. 



Observations. — This species, which was taken probably within a fathom of the bottom, 

 is in a very peculiar condition, which suggests that the animal when captured was 

 approaching the period of exuviation. Most of the new parts are visible beneath the 

 transparent outer covering, so that the next skin can be observed in its more perfect and 

 mature condition. The armature on the rostrum shows that the new teeth correspond 

 in number with those of the preceding moult. 



Bentheocaris stylorostratis, n. sp. (PL CXXIII. fig. 4). 



Carapace less than one-fourth the length of the animal, elevated above the frontal 

 region to a thin, laterally compressed crest that projects over the frontal margin in the 

 form of a rounded rostrum, fringed with slender teeth, of which the anterior is longer 

 than the others, styliform, and projecting straight forwards. The orbit is only 

 imperfectly defined by a small point, beyond which is another that represents the first 

 antennal tooth, and corresponding with the position of the second antennal tooth is a 

 longitudinal ridge. 



