BATHYPELAGIC SQUID BATHYTEXJTHIS 53 



fera apparently inhabits the water la:yer immediately beneath the 

 zone of hi^h productivity, an adaptive advantage commensurate with 

 its anatomical adaptions for a relatively sluggish, upper bathypelagic 

 existence, 



Chun's largest specimen (18 mm ML) from the Indian Ocean, which 

 may be B. hacidifera, was captured in the Indian Ocean Equatorial 

 Water Mass in a plankton net that was towed vertically from 2000 

 meters. Granting that Bafhytenthis normally lives below 500 meters, 

 the temperature-salinity values (Tressler, 1963; Fell, 1965) indicate 

 that Chun's specimen came from temperatures and salinities as low as 

 2° C and 34.7%o at 2000 m to as high as 10° C and 35.1%o at 500 m. The 

 oxygen concentration in shallower portions of this zone ranges from 

 less than 0.5 ml/L at around 500 m to 1.0 ml/L at 1000 m; in deeper 

 portions it rises to about 2.5 ml/L at about 2000 m. If the distribution 

 of B. hacidifera in the Indian Ocean Equatorial waters is governed by 

 similar physicochemical parameters as this species in the Eastern 

 Pacific Equatorial Water it would be found below about 500 m. 

 Oxygen values in the two oceans (ca 0.5-1.5 ml/L) coincide between 

 750-1500 m and temperatures (ca 3.8°-6° C) coincide between 1000 and 

 1750 m. Salinities are high in Indian Equatorial water so there is no 

 overlap of values, but sigma-t values of 27.20 to 27.60 in the eastern 

 Pacific are found between 750 and 1500 m in Indian equatorial waters. 



Further consideration of the distribution of B. hacidifera is given in 

 the main section on distribution. 



Bathyteuthis berryi Roper, 1968 



E*LATES 11-12 A-F 



Bathyteuthis berryi Roper, 1968, p. 169, pis. 5-7. 



Diagnosis. — Protective membranes on arms present, well developed 

 and fleshy proximally, no free trabeculae; suckers on arms extremely 

 numerous, sucker rings with 10-14 protuberances ; gills long and broad. 



DESCRirnoN. — The mantle is very plump and robust; it is bullet- 

 shaped in outline (pi. 11). The widest part of the mantle is about at 

 the midpoint, and the mantle width is 50% of the mantle length. The 

 mantle opening is slightly narrower and the margin bears low, ventro- 

 lateral lobes. The mantle remains broad for much of its length, then 

 tapers and terminates posteriorly in a broad, bluntly rounded tip. 



The fins are short, rounded, and widely separated posteriorly by the 

 blunt tip of the mantle (pi. 11), Anterior insertions are very broadly 

 separated by the dorsal surface of the mantle. Anterior and posterior 

 fin lobes are about of equal dimensions. 



