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Distribution. — Greenland (Kr0yer), Jan Mayen (Norw. North Atl. Exp.), 
the Kara Sea (Stuxberg), the Siberian Polar Sea (Stuxberg). 
Gen. 2. Diastyloides, G. 0. Bars, n. 
Generic Characters .—General appearance that of the genus Diastylis, the 
anterior division being sharply marked off from the posterior and rather tumid, 
at least in the female. Carapace large, with the pseudorostral projection strongly 
prominent. Tail slender. Eye wanting. Superior antennae about as in Diastylis. 
Inferior antennae in female with the last joint very small, tuberculiform, and 
without the apical plumose seta, which is replaced by a few very small auditory 
bristles; those in male fully attaining the length of the body. Mandibles rather 
unlike those in Diastylis, the body forming, as in Leucon, a broad lateral ex¬ 
pansion, and having at the base of the thick molar process a conical projection; 
masticatory part comparatively short and stout, cutting teeth indistinct, spines of 
the inner edge few in number. The other oral parts, as also the legs, about 
as in Diastylis. Pleopoda of male less perfectly developed than in that genus, 
1st pair with both rami uniarticulate, 2nd pair with the rami confluent to a 
single piece. Uropoda with the rami very slender, the inner one generally longer 
than the outer, and scarcely mucroniform, apical spine well defined at the base. 
Telson less produced than in Diastylis, with the apical spinules much larger 
than the lateral ones; in male very much bent, forming above at the flexure 
a projecting angle. 
Remarks.—1 have felt justified in establishing this new genus to comprise 
2 Norwegian species iormerly referred by me to the genus Diastylis, but differing 
from it very pronouncedly in some characters of apparently generic value. The 
structure of the mandibles especially is very unlike that in Diastylis, and much 
more resembling that found in the family Leuconidce. Moreover, the inferior 
antennae of the female are rather different, and the pleopoda of the male are 
less fully developed. It is as yet scarcely possible to state with certainty, if 
there are any species among the exotic Diastylidae referable to this genus, though 
it may probably be the case. 
