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



siderably larger and longer, the first joint not regularly oval, broader at the basal than 

 the distal end, the front margin very convex, and the hinder nearly straight. 



Fifth Perseopods. — The branchial vesicles small and irregular in shape. The first 

 joint of the limb larger than in the preceding pair, much broader above than below ; the 

 third joint also larger than in the preceding pair, like it having spines at seven points in 

 front and at five on the hind margin, which is a little decurrent. The rest of the limb 

 missing. 



Pleopods. — Coupling spines short but strong, with apical hooks and serrate sides ; 

 the peduncles have also some lateral groups of setae and apical rows of spines ; the cleft 

 spines appear to be seven, six, and five in the series on the first, second, and third pairs 

 respectively ; the joints of the rami number from eighteen to twenty. 



Uropods. — Peduncles of the first pair rather longer than the rami, spined along two 

 margins, one of which is produced in a blunt process tipped with a large spine ; the outer 

 ramus rather shorter than the inner, both spined along the margins, and having a group 

 of spines at the blunt apices ; peduncles of the second pair scarcely as long as the outer 

 ramus, which is considerably shorter than the inner ; the margins of the peduncles 

 apically sharp ; the rami with spines along the margins, and a group on the blunt apex ; 

 peduncles of the third pair shorter than the rami, which are subequal, apically acute, with 

 spines and plumose seta? along the margins. 



Telson long and narrow, reaching beyond the peduncles of the third uropods, cleft 

 beyond the centre, slightly dehiscent, the apices narrow but double, the outer point 

 reaching a little beyond the inner, the interstice occupied by two or three cilia or setae ; 

 on the sides near the base there are some minute setules, on the surface near the outer 

 margin above the top of the cleft there are a pair of cilia, and some way below the top 

 of the cleft a spine-like seta attended by a cilium. 



Length. — The specimen, in the position figured, measured, in a straight line from the 

 rostrum to the back of the third pleon-segment, rather more than half an inch. Another 

 specimen measured, within the same limits, over three-fifths of an inch. 



Locality. — Station 161, off Melbourne, April 1, 1874; depth, 33 fathoms; bottom, 

 sand. Two specimens, one of them female. 



Rernarh—Tke specific name is derived from a character well known in the history 

 of Rome. 



Eusiroides pompeii, n. sp. (PI. LXXXIX.). 



Rostrum small, lateral lobes of the head with the front margin straight ; the postero- 

 lateral corners of the first two pleon-segments forming right angles, of the third segment 

 rounded, denticulate, the upward-pointed denticles reaching halfway round the lower 



