REPORT ON THE AMPHIPODA. 673 



The present species resembles the type of the genus in the shape of the hand of 

 the first gnathopods, but it has the wrist of that hand short instead of long, nor in the 

 second gnathopods has it a strong nail like that in the type species. It agrees with the 

 type in the lower antennae, the side-plates of the first and second perseon-segments, and 

 in the pleon. The mouth-organs of Euonyx chelatus, Norman, so far as I can judge 

 from mounted dissections of the type specimen lent me by Canon Norman, show a general 

 agreement with those of the present species, but the palp of the first maxilla has seven 

 spine-teeth on the apex of the second joint, and what appears to be the outer plate of the 

 maxillipeds has the inner margin and apex fringed with nine plumose setae, being at the 

 same time quite devoid of teeth. 



Genus Orchomene, Boeck, 1870. 

 For the original definition of the genus, see Note on Boeck, 1870, p. 399. 



Orchomene musculosus, n. sp. (PI. XX.). 



Head short, lateral lobes protruding, rounded ; back rounded ; lower and hind margins 

 of the first three pleon-segments connected by curves in no way angular, fourth segment 

 with a deep transverse dorsal depression between two humps, sixth segment dorsally 

 ridged or folded on either side of the telson ; small hairs on various parts of the 

 integument. 



Eyes not perceived. 



Upper Antenyiae. — First joint very tumid, scarcely longer than broad, second and third 

 very short, the third excavate on the under side ; flagellum of eleven joints, the first as 

 long as the first of the peduncle, rapidly tapering, the brush formed of very slender 

 cylinders, the remaining joints small, successively narrowing ; some calceoli present ; 

 the secondary flagellum of four joints, the first longer than the other three united. 



Loiver Antenna?. — Gland-cone prominent, not acute ; third joint as long as the first 

 two united, fourth and fifth joints subequal, furred on the upper margin, with some 

 setae on the lower ; flagellum of thirteen joints, the first six or seven together equalling 

 in length the fifth joint of the peduncle ; some calceoli present. 



Mandibles. — Cutting edge convex, with a small downward-directed tooth at the top, 

 and a small tooth behind the rounded lower angle ; the secondary plate of the left 

 mandible is a narrow, slightly curved strap, with the end divided into four small teeth ; 

 the spine-row of three short curved spines, broad at the bases ; behind these the margin 

 is furred for some distance back to the backward-pointing, narrow, dentate crown of 

 the molar tubercle, above the hinder portion of which is a bush of fur ; the articular 

 condyle is directed far forward ; the palp is set far back, behind the molar tubercle, its 



(ZOOL. CHALL. EXP. — PABT LXVU. — 1887.) XxX 85 



