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



rigid and armed with a small tooth. Mandible furnished with a molar process, 

 psalistoma, and synaphipod. Second pair of gnathopoda pediform. First and second 

 pairs of pereiopoda chelate. Pleopoda biramose. Rhipidura well developed. 



Caricyphus, 1 n. gen. 



Carapace less than one-third the length of the animal, dorsally smooth and anteriorly 

 produced to a small, sharp-pointed rostrum. The fronto-lateral angle is produced to a 

 small tooth. 



The pleon is long, the first three somites are as deep as the carapace and the 

 succeeding ones are narrow and slender. The third somite is large, dorsally produced in 

 the middle, and abruptly descends to the posterior margin, where it articulates with the 

 fourth somite at a right angle with the preceding somites. 



The telson is long and tapering. 



The ophthalmopoda are well developed. 



The first pair of antennae is binagellate. 



The second pair of antenna? carries a large scaphocerite and a long flagellum. 



The mandibles are without a synaphipod. 



The first pair of gnathopoda is subpediform. 



The second pair is pediform. six-jointed, and carries a long uniarticulate basecphysis. 



The first pair of pereiopoda is chelate and carries a long, flat, uniarticulate baseqmysis. 

 The second pair is a little larger than the first, chelate, and supports a similar 

 basecphysis. The third pair is simple, slender, subequal in length, and also bears a 

 similar basecphysis. The fourth and fifth pairs resemble the third in form and size, but 

 do not carry a basecphysis. 



The pleopoda are biramose. 



The terminal pair forms part of the rhipidura and is biramose, the branches being 

 subequal with the extremity of the telson. 



Geographical Distribution. — There are four or more species, and they range from the 

 central area of the Pacific to the China Seas. 



Observation. — They are evidently the young of some unrecognised form. The 

 specimens were few, generally one of each species, and at this stage the mandibles are 

 without a synaphipod. The pleonic hump is suggestive of a comparison with the genus 

 Tozeuma. 



Caricyiihus cornutus, n. sp. (PL CXXI. fig. 2). 



The carapace is about one-fifth the length of the animal and is anteriorly produced to 

 a rostrum that is sharp pointed and armed on the upper surface with two sharp teeth. 



1 xxi>ls, Kvtpo;. 



