72 G. 0. SARS. CRUSTACEA. [norw. POL. EXP. 



The natatory legs (figs. 9 — 11) considerably increase in length posteriorly, 

 the 4th pair being nearly twice as long as the 1st. In structure they agree, 

 on the whole, with those in the preceding Calanoids, the inner ramus being 

 much smaller than the outer, uniarticulate on the 1st pair, biarticulate on the 

 2nd, and 3-articulate on the 2 posterior pairs. Both rami are comparatively 

 more slender than in the type species, but are otherwise of exactly the same 

 structure. The last pair of legs are, as in the type species, wholly absent. 



The adult male, of Avhich only a solitary specimen was found, closely 

 resembles the male of P. elongatus, but is considerably larger, measuring in 

 length 1*80 mm. It is easily recognizable from the female, both in its external 

 appearance and in the structure of the several appendages, which, on the 

 whole, closely agrees with that in the type species. 



The last pair of legs (fig. 13) are very slender, each leg forming a simple 

 stem, which, however, is rather different on the two sides. The left leg is 

 a little longer than the right, and is composed of 5 distinctly-defined joints, 

 the first 2 of which may represent the basal part, the other 3 the terminal 

 part or more properly the outer ramus. The joints of this latter part rapidly 

 diminish in size, the 1st being about the length of the 2nd basal joint, whereas 

 the last is extremely small and hook-shaped. The right leg, contrary to what 

 is the case in the left, has the 1st basal joint considerably larger than the 

 2nd, and much more dilated at the base. The terminal part forms a slender 

 styliform piece, occupying considerably more than half the length of the leg, 

 and exserted to a very acute point. In the type species this piece is divided 

 into 2 well-defined joints, which, however, in the present form are scarcely 

 distinguishable at all. 



Occurrence. This form was found rather abundantly in the samples 

 taken between the the 12th and 24th October, 1893, north of the New Siberian 

 Islands. As stated above, it occurred here together with the type species, 

 from which it was at once distinguished by its much larger size. It was 

 also found occasionally in 2 other samples taken on the 11th and 19th April, 

 1894, in about the 80th degree of latitude. 



