52 
slight swelling of the carapace on each side at the base of the pseudorostral 
projection. Appendages of the usual structure. Length 11 mm. 
Remarks. —I cannot doubt that this is the form originally recorded by 
Goodsir as Alauna rostrata. There is no other species of Diastylis, which agrees 
better with the figure and description given by that author, and its occurrence 
in comparatively shallow water would also seem to point to the identity of these 
2 forms. The Diastylis Icevis of Norman is unquestionably the same species. By 
the perfectly smooth carapace, this form is easily distinguished from any of the 
preceding species, somewhat resembling in this respect the next species, D. tumida 
Lilljeborg, which, however, is a true deep-water form, and differs, among other 
things, in the larger size of the carapace, and in the different shape of the telson. 
Occurrence. —I have met with this form only in a few places on the south 
coast of Norway, viz, in the outer part of the Christiania Fjord, at Farsund, and 
at Egersund. In all 3 places it occurred in only a few fathom’s depth, on a 
sandy bottom covered by a thin layer of mud. 
Distribution. —Kattegat (Meinert), Heligoland (Ehrenbaum), British Isles 
(Goodsir), Stats. 6, 11, 18 of the Porcupine Expedition (Norman). 
6. Diastylis tumida, (Lilljeborg). 
(PI. XL.) 
Cuma tumida , Lilljeborg, 0fvers. af Vetensk. Akad. Forliandl. 1855, p. 119. 
Specific Characters. — Female. Body rather robust, with the anterior di¬ 
vision greatly tumefied, and of rounded ovoid form, with the dorsal face boldly 
arched. Carapace very large and deep, more than twice as long as the exposed 
part of the trunk, and considerably vaulted in its posterior part; surface perfectly 
smooth, only clothed with scattered short hairs; pseudorostral projection not much 
produced, with the tip very slightly upturned; subrostral corners well marked, 
almost rectangular. Last pedigerous segment with the lateral parts rounded oh 
behind. Tail about the length of the anterior division, segments simple, unarmed. 
Eye well developed and rather conspicuous, appearing as a distinctly projecting 
tubercle at the end of the frontal lobe. Superior antennae slender, with the 
peduncle reaching far beyond the tip of the pseudorostral projection, its 1st 
joint shorter than the other 2 combined and unarmed. First pair of legs about 
the length of the carapace, basal joint much shorter than the remaining part of 
the leg, the last 3 joints of rather unequal length, the penultimate one being 
much the longest, last joint comparatively short, not even attaining half the 
length of the penultimate one; 2nd pair with the ischial joint produced below to 
