80 THE ROYAL SOCIETY OF CANADA 
differs in the proportions of the urosome, the genital segment being 
slightly longer and the furcal limbs markedly shorter; thus, in C. 
tenuis the furca is twice and in C. lubbockii nearly three times as long 
as the anal segment, while in C. affinis the two segments have almost 
the same length, the furca being but slightly the longer. Furthermore, 
in C. affinis the furca and anal segment taken together are slightly 
shorter than the genital segment, while in fenuis and lubbockii-their 
combined lengths markedly exceed that of the preceding segment. 
The absence of curvature in the terminal seta of the exopodite of the 
second pair of thoracic legs also distinguishes affinis for both the other 
species. 
I. C. Thompson! has recorded the occurrence at Port Townsend 
of two species of Corycaeus, C. pellucidus and C. obtusus. The latter 
is at once distinguishable from affinis by its possession of but a single 
seta on the rudimentary endopodite of the fourth pair of thoracic 
legs. What the form recorded as pellucidus may be is uncertain, 
since Dana’s original description of the species, based mainly on the 
occurrence of a beak-like prolongation of the ventral keel, does not 
differentiate it from several other species that show the same peculiari- 
ty. Of the later authors who have recorded its occurrence, Lubbock 
and Thompson simply mention it without any description, and Bate 
in the ‘Challenger’ Reports describes a pellucidus which may or may 
not be identical with Dana’s form, but at all events differs from affinis, 
markedly in the form of the second antennæ which approximates that 
shown by C. rostratus Claus. Bate, indeed, gives this last name as a 
synonym of pellucidus, but owing to the uncertainty that exists as to 
what pellucidus really is the identification of rostratus with it seems 
unadvisable, and affinis must also be regarded as distinct and closely 
related, apparently, to fenuis and lubbockit. 
A single sample of a fourth Copepodan species was observed, 
this individual belonging to the Harpacticid genus Idya. It seemed 
to be closely related to, if not identical with, I. furcata (Baird) Sars, 
but its preparation was not quite successful, and the identity, conse- 
quently, not fully established. 
And finally, mention should be made of a Copepodan metananplius 
that occurred in considerable numbers. In details of form this larva 
resembled so closely that of Calanus finmarchicus (Cetochilus septen- 
trionalis ) described by Grobben? that it must be referred to that 
species, even although no adults were obtained in this particular 
collection. They were observed, however, in collections taken at 
1 Proc. Liverpool Biol. Soc. XII, 1898, p. 87. 
2C. Grobben. Arb. Zool. Inst. Wien. III. 1881. 
