120 U.S. NATIONAL MUSEUM BULLETIN 291 



Four captures were made between 2.5° and 3° C at 55° to 57°S; 

 there were four juveniles and two adults (at 1400 m only). Two cap- 

 tures were made between 3° and 4° C with simultaneous temperatures 

 of 3.10° and 3.88° C; they contained two larvae and one juvenile. In 

 the subantarctic waters above the 2.5° isotherm and south of 55°S the 

 five captures in less than 1000 m took six specimens, five of them 

 juveniles. The one adult, however, had a simultaneous temperature of 

 2.2° C, while the simultaneous temperatures of its two closest neigh- 

 bors were 3.10° and 3.88° C. Except for that one specimen, adults were 

 not taken until a depth of 1400 m, and then two of the four specimens 

 from the two tows were juveniles. Therefore, in the convergence zone 

 the eight shallowest captures (725 m to 1250 m) were comprised 

 of larvae and juveniles of Bathyteuthis with the exception of one 

 specimen. 



The capture points in the Peru Current north of 55 °S are widely 

 scattered but give useful information. The four captures taken in 

 waters shallower than the 2.5° isotherm that lies between 1600 m and 

 1750 m comprised a total of 21 specimens; only three of these were 

 as large as 21 mm in mantle length. Of these three, one was a juvenile 

 male, one was a maturing male and one was a mature male. The re- 

 maining 18 specimens ranged from 6 to 19 mm. The tow at 1850 m at 

 33°S was close to the 2.5° isotherm and contained two maturing fe- 

 males of 28 and 29 mm, three juveniles between 13 and 18 mm, and 

 one larva of 9 mm. The seven deeper tows, six of them below the 2° 

 isotherm, captured many adults; of the 27 specimens 20 were maturing 

 or ripe adults. 



Water movements along the eastern boundary of the Peru Current 

 are extremely complex and the entire region is marked by periodic 

 upwellings. It is possible that the shallow catches in the Peru Current 

 represent specimens that were borne upward in upwelled water masses. 

 Seven tows are plotted below 2500 m. The occurrence of B. ahyssicoJa 

 at these depths is uncommon, but wlien the proper conditions prevail 

 it lives at those depths. All seven captures were made at temperatures 

 between 1.4° and 1.8° C. A later section shows that B. ahyssieola prob- 

 ably does not often exceed 2500 m in depth and that s]^ecimens recorded 

 from great depths probably come from slightly shallower in the zone 

 of abundance that ends at about 2250 m. This may apply particularly 

 to the populations in the Antarctic where B. ahyssicola is so abundant. 

 At least the adults in the six deep captures between about 35° to 40°S 

 in the Peru Current probably came from close to the depths plotted, 

 because the temperature at those depths corresponds to the tempera- 

 tures where B. ahysi^icola is most abundant in the antarctic region. 

 Perhaps the few juveniles caught in these tows came from shallower 



