506 



projects more than in pereopods I and the tip is stretched; the process of 

 the chela is long, markedly extending beyond the base of the claw, its tip 

 bent such that it makes a cross with the claw when the chela is closed; the 

 6th segment has a slightly bulged anterior margin and straight denticulate 

 posterior one; the inner margin of the chela is armed with not very high, 

 strong, blunt-tipped denticles arranged uniformly, with small setae between 

 them; on closure of the chela the denticles of the distal margin of the 5th 

 segment fit snugly into the corresponding notches of the posterior margin 

 of the 6th. The maximum width of the flat 2nd segment of pereopods V-VII 

 is shifted proximally. The 2nd segment of pereopods V is 1.5 times longer 

 than wide, the posterior margin bulged, the anterior margin almost straight, 

 weakly denticulate and armed with spiniform setae; the 4th-6th segments 

 also bear setae along the anterior margin. The width of the 2nd segment 

 of pereopods VI is appreciably more than its length, the posterior margin 

 abruptly bulged, the anterior indistinctly denticulate, and distally bears 

 sparse setae; the 4th-5th segments are armed anteriorly with setae; the 

 setaceous ornamentation of the 6th segment is finer and more uniform. 

 The 2nd segment of pereopods VII is broadened, pyriform, and equal to or 

 slightly shorter than the rest of the leg, which consists of narrow virgate 

 segments. 



Ornamentation of the epimerons is characteristic of this species: 

 besides posterior distal denticles, the epimeral plates have a medial denti- 

 cle on the lower margin, especially noticeable in females, less so in males. 



The basipodite of uropods I is much longer than that of uropods II 

 and, similar to the rami, is finely denticulate on both sides; the endopodite 

 is slightly longer than the exopodite. The exopodite of uropods II and III 

 is shorter than the endopodite and smooth on the outer side. The telson 

 is approximately equal in length to the last urosomite, gradually narrows 

 towards the tip, and proximally has smooth margins becoming denticulate 

 distally. 



The body proportions are fairly stable: the head is relatively shorter 

 than in O. piscator, constituting in females about 1/5 the body length, 

 in males slightly more. The pereon in females is always longer than the 

 pleon, in males the two are equal in length. The urosome constitutes 

 2/9-1/4 the total body length. The brood chamber is almost bordered by 

 pereon somites V and VI. 



Distribution: Widely distributed in tropical regions of the ocean and 

 lives at the surface to a depth of 100 m, rarely deeper. The smaller form, 

 evidently, is confined to equatorial waters. 



3. Oxycephalus latirostris Claus, 1879 (Fig. 220) 



Claus, 1879a: 71; Bovallius, 1890: 66; Pirlot, 1938: 367; Page, 1960: 

 26. — pectinatus Bovallius, 1890: 64. — notabilis Spandl, 1927: 182. 



