18 
THE VOYAGE OF H.M.S. CHALLENGER. 
Achseopsis, Stimpson. 
Achseopsis, Stimpson, Proc. Acad. Nat. Sci. Philad., p. 218, 1857. 
,, Miers, Journ. Linn. Soc. Lond (Zool.), vol. xiv. p. 645, 1879. 
This genus, which apparently represents the northern genus Inaclius in the southern 
hemisphere, is distinguished from it merely by having the postocular as well as the 
prseocular spine distinctly developed, and by the more or less falciform dactyli of the 
three posterior ambulatory legs. 
Two species of the genus have been described, which both occur at the Cape of Good 
Hope, in shallow water, Achseopsis spinulosus, Stimpson, and Achseopsis giintheri, Miers, 
the latter distinguished from the type by having but a single very long perpendicular 
spine on the gastric region. 1 
Achseopsis spinulosus, Stimpson (PI. I. fig. 4). 
Achseopsis spinulosus, Stimpson, Proc. Acad. Nat. Sci. Philad., p. 218, 1857. 
Three males were collected in Simon’s Bay in 10 to 20 fathoms, and one in 5 to 18 
fathoms ; here also the types of the species were obtained. 
In the specimens examined, the ambulatory legs, although granulated, can scarcely 
be described as spinuliferous, as in Stimpson’s description. 
The description (except measurements) which follows, and the figure are from adult 
dried examples in the collection of the British Museum, which are in more perfect 
condition than the Challenger specimens. 
Carapace ovate-triangulate, moderately convex, and rounded on the sides of the 
branchial regions, with three spines disposed in a triangle on the gastric region, one on 
the cardiac, and two on each branchial region, on the dorsal surface (there are sometimes 
some smaller branchial spinules). There is one (or sometimes two) spinules above or in 
front of the eye-peduncles, and a well-developed postocular spine. The hepatic region 
is prominent and rounded and bears several small spinules, and there are several on the 
sides of the branchial regions. The rostrum is composed of two small acute lobes or 
spines which do not exceed in length the interocular portion of the front. The post- 
abdomen in both sexes is six-jointed. The eyes are of moderate size, and the cornese 
have usually a small distal tubercle. The basal joint of the antennae is slender, 
longitudinally sulcated, and bears several small spinules ; the flagella are exposed and 
visible in a dorsal view at the sides of the rostrum. The merus of the exterior maxilli- 
pedes is narrower than the penultimate joint, is not distally truncated, and bears the 
next joint near to its antero-external angle. The chelipedes (in the adult male) are 
1 Possibly the Australian species Stenorhynchus curvirostris, A. Milne Edwards, and Stenorhynchus fissifrons, 
Haswell, which have not been figured, may be referable to this genus. Stenorhynchus brevirostris, Haswell, is, I think, 
a species of Achseus. 
