YOUNG: VERTICAL DISTRIBUTION AND PHOTOSENSITIVE VESICLES 



where they exhibited an ontogenetic descent. The 

 depth range for specimens 5^20 mm ML was 725 to 

 1,065 m; nearly 909^ of the animals occur between 

 700 and 950 m and nearly 60'7f between 750 and 

 850 m. Gravid and brooding females were found at 

 the extremes of this range. Two gravid females 

 were captured at 1,050 and 1,065 m while three 

 spent and presumably brooding females were 

 taken between 725 and 800 m. As in£'. pygmaea, 

 the gravid and spent females have a very heavy 

 pigmentation and lack most of the iridophores 

 present in younger specimens. Five such females 

 were captured in horizontal tows. One gravid 

 female with a sperm mass embedded in the 

 gelatinous tissue between the second and third 

 arms was taken at 1,050 m. Another taken at 

 1,065 m had been gutted in the trawl but had not 

 spawned: the musculature was firmer than in 

 spent females, and the catch contained a large 

 number of octopod eggs which undoubtedly came 

 from the ruptured ovary. Three specimens taken 

 between 725 and 800 m probably had spawned: 

 two had depleted ovaries and the third was gutted 

 but had deteriorated musculature. In the same 

 tow with the last specimen were four newly 

 hatched larvae, presumably from the brood of the 

 female. One large, heavily pigmented female 

 taken in an oblique tow had the remnants of an 

 egg string dangling from one of the large suckers 

 of the third arm. Two eggs were completely en- 

 gulfed by the sucker, while a third dangled from 

 the broken egg string extending from the sucker. 

 No mature males were taken. 



MANTiE LENGTH 



20 40 60 



MANTLE \.l NGTH.m m 



Figure 46. — A. Vertical distribution of Amphitretus pelagicus 

 (squares) and Vitreledonella richardi (circles). B. Vertical dis- 

 tribution ofVampyroteuthis infernalis . Half-closed circles repre- 

 sent a twilight capture. Otherwise symbols as in Figure 1. 



Photosensitive Vesicles 

 The vesicles are as in E. pygmaea. 



Family Amphitretidae 



Amphitretus pelagicus Hoyle 1885 



Vertical Distribution (Figure 46A) 



Two specimens were taken at night in the upper 

 350 m. 



Photosensitive Vesicles (Figure 44B) 



Amphitretus pelagicus has one set of organs. 

 They lie on the stellate ganglia immediately an- 

 terior to the entry points of the pallial nerves. 

 Each organ consists of a large complex of a dozen 

 or more generally circular vesicles which cover 

 most of the anterior wall of the ganglion. 



Family Vitreledonnelidae 



Vitreledonnella richardi Joudin 1918 



Vertical Distribution (Figure 46A) 



Four specimens were captured. One small 

 specimen was taken in an oblique twilight tow 

 between the surface and 400 m. Two other small 

 specimens were taken between 600 and 650 m 

 during the day. One large specimen was captured 

 at 775 m during the night. 



Photosensitive Vesicles 



An organ consisting of a single spherical vesicle 

 is located on the posterior margin of each stellate 

 ganglion. 



Order Vampyromorpha 



Family Vampyroteuthidae 



Vampyroteuthis iuferualis Chun 1903 



Vertical Distribution (Figure 46B). 



Eleven specimens were captured. Ten of the 11 

 were taken between depths of 800 and 1,200 m. 

 The remaining specimen came from an open ob- 

 lique tow that fished between 1,100 and 1.900 m. 

 Diel vertical migration does not occur. 



607 



