1250 THE VOYAGE OF H.M.S. CHALLENGER. 



Lower Antennse very little longer than the peduncle of the upper antennae, the first 

 two joints closely coalesced, the gland-cone small, scarcely decurrent, the third joint 

 very little longer than the two preceding united ; the fourth joint considerably longer 

 than the three preceding together ; the fifth a little longer than the fourth ; the flagellum 

 not so long as the fourth joint of the peduncle, the first joint longer than the second, 

 each carrying apical cilia or setules, the second not by any means rudimentary, as would 

 be required by Kr0yer's definition of the genus JEgina. 



Mandibles. — The details not clearly made out ; the cutting plate cut into several 

 teeth ; the palp elongate, the first joint a good deal longer than broad, the second more 

 than twice as long as the first, with one or two setules near the centre of the front 

 margin ; the third joint rather longer than the second, with four or five setae or slender 

 spines on the oblique apical margin. 



First Maxillae. — -The outer plate with five or six small spines on the apical margin ; 

 the palp with three or four spinules on the apical margin of the second joint, and one or 

 two setules on the surface or outer margin. 



Second Maxillx. — Inner plate small, much shorter than the outer, with four or five 

 apical setules ; the outer plate with five or six apical setules or slender spines, longer 

 than those on the inner plate. 



Maxillipeds. — Inner plates very small, scarcely reaching the base of the first joint 

 of the palp, with a couple of setules on the rounded apex ; the outer plates reaching a 

 little beyond the first joint of the palp, with two setules on the apex and three on the 

 inner margin ; the first joint of the palp the shortest, the second longer than the third, 

 the third with setules about the apex, the fourth not much, if at all, shorter than the 

 second, curved, acute. 



There is a great resemblance between the mouth-organs of this species and those of 

 Caprellinopsis tristanensis, but the minuteness of the specimens made a thoroughly 

 satisfactory comparison of the details impracticable. 



First Gnathopods attached close to the maxillipeds. The first joint about as long as 

 the hand, widening a little distally, the front margin nearly straight ; the second joint 

 scarcely longer than broad, with a cilium near the apex behind ; the third joint longer 

 than the second, with two spines and a seta at the tolerably broad apex ; the wrist about 

 as long as the third joint, widening distally, and on the lower margin armed with three 

 spines ; the hand much longer and broader than the wrist, more or less oval, the front 

 margin nearly three times as long as the hind margin without the long oblique palm, 

 which is defined by some very small palmar spines and fringed with a few setules ; there 

 are two or three small groups of setiform spines on the surface near the front margin ; 

 the finger is long, curved, acute, matching the palm, carrying a dorsal cilium near the 

 hinge, and a couple of cilia at the base of the short nail or nail-like tip. 



Second Gnathopods. — As with the other limbs there is a rudimentary side-plate. 



