from the Gulf of St. Lawrence. 453 
This species'approaches very closely to C. abyssicola, Sars, 
and C. Stimpsoni, Brady. From the former it differs chiefly 
in having a less pronounced marginal belt, a more rugged 
surface, and a less angular outline when viewed from above ; 
from the latter in the absence of any sharply cut longitudinal 
crests, and by its more rounded contour and elevated anterior 
margin. There is, however, considerable diversity amongst 
the specimens here grouped under the specific name canadensis, 
and it is possible that a more extended series might have 
shown that they belong to two or more species. ‘The chief 
difference resides in the surface-ornament, some exhibiting 
several short, rough and abruptly elevated ridges, others being 
only moderately pitted, while some (from one of which our 
drawings are taken) are intermediate in character, being rather 
delicately ridged, chiefly on the posterior half, and vaguely 
pitted and ridged in front. 
Cythere Dawsont, nov. sp. (Pl. XIX. figs. 8-10.) 
This is apparently a very distinct species; but the single 
specimen contained in these dredgings was unfortunately lost 
while the drawings here given were in course of completion ; 
so that I am unable to describe it as accurately as might be 
wishe 
Cytheridea elongata, Brady. 
e specimen so named is very doubtfully referred to this 
species; and the same remark may apply to. . 
Xestoleberis depressa, Sars, 
of which only a poor specimen occurs, and may perhaps be- 
long to some other member of the genus. 
