356 



FISHERY BULLETIN OF THE FISH AND WILDLIFE SERVICE 



short fine hairs. Remaining cephalic appendages 

 similar to those in armatus. 



First legs with external spines of exopodite (Re) 

 vmequal ; fii-st segment ( Rej ) with reduced spine ; 

 Re2 with thick spine barely longer than length of 

 segment ; Res with stylifonn spine about two times 

 length of segment (fig. 8). Remaining legs with 

 dorsal and ventral borders of each external spine 

 bearing fringe of numerous closely spaced hairs 

 (fig. 7). 



Endopodite (Ri) of first leg with lateral shoul- 

 der broad, truncate, and bearing recurved spinules 

 distad ( fig. 8 ) . I-«gs 2-4 with Ri bearing spinules 

 differing in number and arrangement from those 

 in armatus. Leg 2 with proximal portion of Ria 

 bearing arc of four large spinules ; distal portion 

 with three pairs of spinules, single spinule between 

 first and second pair (fig. 7). Leg 3 with Rij 

 bearing about 11 subequal spinules arranged along 

 outer half of segment in proximal row of four, 

 distal cluster of seven ; Rig with total of about 12 

 spinules including proximal cluster of seven, two 

 distal rows of three each (fig. 10). Leg -4 with 

 Rij bearing distal cluster of numerous thick hairs 

 and a row of six spinules (fig. 9) . Fifth leg lack- 

 ing as in other species of genus. 



Adult male : Differs from pacifim/s and similis 

 chiefly in details of fifth legs. 



Fifth legs approximately two times total length 

 of abdomen plus furcal rami, almost entire length 

 of Re extending posteriad beyond abdomen (fig. 

 3). Right Ri unisegmental, less than one-third 

 length of Rei ; Ri with truncate apex bearing 

 short acuminate filament. Right Re with two seg- 

 ments, second segment weakly sclerotized with 

 proximal portion bearing low lamella, distalmost 

 portion expanded. Left Ri two-segmented, about 

 as long as left Rei ; segmentation of left Ri ap- 

 parently variable in si?mlis, bisegmental according 

 to Vanhoft'en (1907: pi. 22, fig. 30), unisegmental 

 in Sars (1902: pi. 20). I^ft Re with three seg- 

 ments; Re, bearing distal tuft of styliform 

 spinules; Re, hirsute along inner face; Rea and 

 Res about equal in length, each shorter than Rci 

 (fig. 12). 



Types {cf. Localities). — All deposited in United 

 States National Museum. Male holotype, No. 

 99204, selected from material of Alaska, cruise 4, 

 station 11. Male paratypes, No. 99205 {Alaska, 



cruise 4, station 11) ; female paratype, No. 99206 

 (Alaska, cruise 8, station 2). 



Further description. — Abdominal segments in- 

 cluding furcal rami with following proportional 

 lengths : female (segments 3 and 4 taken together) 

 39; 19; 20; 22 ( = 100) ; male (segments 4 and 5 

 taken together) 15 ; 29 ; 21 ; 19 ; 16 (=100) . 



Female with terminal spines of legs 2^ bearing 

 17, 19, 18 serrations, respectively. Leg 4 about one- 

 third longer than abdomen. Rostrum similar to 

 that of pcwifciis. 



Male with terminal spiniform processes of 

 thoracic fusion segment IV-V produced postero- 

 mediad (fig. 4). First antennae elongated, ex- 

 tending to furcal rami ; right antenna with 20 

 visible segments, primitive segments 8-10, 12-13, 

 20-21, 24-25 fused. Left antenna with 21 visible 

 segments, primitive segments 20, 21 not fused. 

 Remaining cephalic appendages reduced as in 

 other species of genus. Ri of legs 2-4 with spi- 

 nules as in female. 



Ecology. — There is evidence that the new species 

 differs from previously described members of the 

 genus with respect to temperature requirements. 

 One of the three, B. pacificus, is known only from 

 the boreal to subarctic waters of the Sakhalin Sea. 

 The other two, siiJiilis 'and arnuittts, appear to 

 range circumglobally from the arctic to the tropics 

 (Rose 1933, Wilson 1950, Vervoort 1952). How- 

 ever, despite the latitude, the three species are 

 typically confined to deep water at or near the 

 ocean bottom (Sars 1902, Brodski 1950, Vervoort 

 1952). In those instances where collecting data 

 are available for the more infrequent records of the 

 genus from the lower latitudes, armatti^ and similis 

 occurred only in vertical tows taken from depths in 

 excess of 200 fathoms (Pacific Ocean: Scott 1909; 

 Wilson 1942, 1950). According to Sverdrup, 

 Johnson, and Fleming (1942: 690-695, fig. 191, 

 chart 5) temperatures at 200 fathoms in tropical 

 latitudes of the Pacific do not exceed 10° C. and, in 

 fact, usually approximate 5°C. or less. It is well 

 known that subsurface temperatures in boreal and 

 arctic waters of the northeastern Atlantic are be- 

 low 10° C. Therefore, the approximate tem- 

 perature range of previously described species of 

 the genus would appear to lie between 0°-10° C. 



With the new species, water temperatures at the 

 time and depth of capture ranged from a low of 



