YOUNG: VERTICAL DISTRIBUTION AND PHOTOSENSITIVK VESICLES 



Day and night captures were in the same depth 

 range, indicating that diel vertical migration does 

 not occur. The three specimens captured at the 

 greatest depths were gravid females. The speci- 

 men captured at 910 m had sperm receptacles im- 

 bedded in the back of the head and in the an- 

 terodorsal surface of the mantle. The nidamental 

 and oviducal glands were greatly enlarged and the 

 entire visceropericardial coelom was packed with 

 large eggs. The muscular tissue was slightly 

 flabby. The specimen captured at 1,125 m exhi- 

 bited almost identical features. The specimen cap- 

 tured at about 1,100 m had similarly placed sperm 

 reservoirs, less extensively enlarged nidamental 

 and oviducal glands, and lacked eggs (apparently 

 due to damage during capture*. This specimen 

 exhibited no sign of muscular degeneration. The 

 mantle cavity of this specimen had two very long 

 arms from another specimen (presumably a male) 

 attached to the inner wall of the mantle. The 

 largest specimen was an immature female. Its size 

 was largely due to its fixation in a relaxed state. In 

 this species, the pen is extraorinarily delicate and 

 accurate measurements of contracted, crumpled 

 specimens are nearly impossible. 



Photosensitive Vesicles (Figure 403) 



Bathothauma lyrommQ has a single set of or- 

 gans. Each organ consists of a flat oval vesicle 

 located on the posteroventral surface of the pedun- 

 cle complex. No screening pigment is present. 

 Slight positive allometric growth of the vesicles 

 occurs from juveniles to adults. 



Galiteuthis pacifica (Robson 1948) 



Vertical Distribution (Figure 42) 



The 27 specimens captured indicate a broad ver- 

 tical range for this species. Fourteen of the 19 

 captures of specimens >20 mm ML came from 

 depths of 700 m or more. The data indicate that 

 diel vertical migration does not occur. 



Photosensitive Vesicles 



The vesicles of this species are similar to those of 

 G. phyllura described by Young ( 1972a). A single 

 set of organs is present. Each organ consists of a 

 large oval vesicle attached to the posteroventral 

 surface of the peduncle complex. Considerable 

 positive allometric growth of the vesicles occurs. 



0| i r 



200 



400- 



E 



x" 



■600 



800- 



1000- 



1200 



1 — ' — r 



6oo o 

 o 9 •■ o o 



1350m 

 .J I . 1 I 



10 20 30 40 50 260 



MANTLE LENGTH, mm 



FiGL'RE 42. — Vertical distribution of Galiteuthis pad fica . Sym- 

 bols as in Figure 1. 



Order Octopoda 



Family Bolitaenidae 



Eleciouella pygmaea Verrill 1884 



N'ertical Distribution (Figure 43) 



Eighty specimens were captured. Day and night 

 captures were in the same depth range (except 

 above 300 m where day trawling was minimal), 

 indicating that diel vertical migration does not 

 occur. Most specimens between 5 and 15 mm ML 



\^ o • • 



L». ,,.,,, J' f» 



-I 1 1 r 



-| r 



"nil 



'9 J 0, 



nt, 



20 ;5 30 



M AN T I E le NGTM, 



Figure 43. — Vertical distribution oi Eledonella pygmaea. Cir- 

 cles with crosses represent brooding females. Double circle rep- 

 resents a gravid female. Otherwise symbols as in Figure 1. 



605 



