4.".l) TAOK SKOOsriRllO 



majority of species the trunlv is considerably stronger and also somewhat longer than in the 

 female and is furnished with very numerous sensorial filaments along almost its whole length; 

 the six distal ones of these filaments are jjractically quite like the six distal sensorial filaments 

 on this bristle in the female, with which they are also 2;)robably homologous; the other sensorial 

 filaments, the accessory ones, are about as long as but somewhat narrower than those just 

 mentioned; they are situated on one side — on the anterior-medial side — of the bristle along 

 the proximal part of the stem of the bristle, and are arranged more on all sides distally; they 

 are also, at least partly, arranged in a number of transversal rows (in the cases investigated about 

 thirteen to twenty rows were observed). In a number of forms (cf. A. curta p. 501 of this 

 treatise) this bristle shows quite the same type as in the female. G. W. MtlLLER describes 

 (1908, p. 93) a species A. ovalis (= A. glacialis, G. W. MULLEli, 1912), which, as is 

 shown on p. 503 of this treatise, is very closely related to A. curta; the male of this 

 species appears to be characterized by having this bristle rather weakly developed and 

 provided with only a few sensorial filaments, according to the text ,,etwa vier", according 

 to the accompanying figure five (pi. 8, fig. 15).* The a-claw is rather considerably 

 weakened, but is distinctly claw-like. The b-bristle is only rather slightly lengthened; its sen- 

 sorial filaments, which are only slightly or else not at all increased in number (in all the cases 

 investigated the number was increased by only a single filament), are somewhat more unifoi-mly 

 distributed along the proximal half of the bristle. The c- and f-bristles are of the same type 

 as in the female, but are enormously lengthened, being about V/3 times or IV2 times as long as 

 the shell, and have a considerably greater number of sensorial filaments. Tlie g-bristle is 

 onlv slightly longer and the number of its sensorial filaments is rather slightly greater than 

 in the female. The f-bristle is not, as in the female, directed rectangularly forward, but 

 in the longitudinal direction of the antenna, the b-, c-, and g-bristles are also pointed some- 

 what less forward than in the female. On the end joint there is latero-posteriorly a powerful 

 chitinous verruca, which is quite absent in the female (cf. fig. 8 of A. norvegica). From it the 

 e-bristle issues basally-anteriorly ; tliis bristle is of the same type as in the female; it always 

 seems to penetrate between the c- and g-bristles and is held medially of these bristles (cf. 

 fig. 8 of A. norvegica, fig. 11 of A. Grimaldi and fig. 7 of A. curta). I could not observe any 

 trace of the d-bristle. Whether this latter bristle is developed in the males of such forms as 

 have it developed in the females, I cannot decide, as no such forms were present in my collection. 

 The pilosity is weaker than in the females. 



Second antenna: — 



Female: — The p r o t o p o d i t e has a very short bristle distally-mediaUy close 

 to the exopodite; this bristle was observed in all the species dealt with in this treatise except 

 A. Grimaldi and its variety. The e x o p o d i t e is about as long as th(> protopodite; the 

 jjrojjortions between its joints are as follows: 



I : II : III : IV : V : VI : VII : VIII : IX = 30 : G : 3 : 3 : 3 : 3 : 3 : 3 : 2, 

 i. e. the first joint is about as long as or somewhat longer than all the following joints together, 

 the second joint is atxnit as long as the total length of the two Following joints. The first joint 



« ('.. W. Ml 1,1 Kii .■vi.lnilly Kiiiiilcil oni' iil' \\\r lil;iinciils ;is 1 lir dishil |.;iit (iT llii' liiisllc. 



