YOUNG: VERTICAL DISTRIBUTION AND PHOTOSENSITIVE VESICLES 



CPV 



P.PV 



Figure 27. — A. Photosensitive vesiclesof 

 Mastigoteuthis famelica. B. Photosensi- 

 tive vesicles of Joubiniteuthis portieri. 

 Abbreviations as in Figure 2. 



The central organs are located on the posterior 

 margin of the optic stalk and consist of a dozen or 

 so independent spherical vesicles. The posterior 

 organs lie on the posterolateral surfaces of the 

 optic lobes opposite the lateral attachment of the 

 head retractor muscles. Each organ consists of a 

 string of several layers of circular or oval vesicles. 

 A few scattered vesicles occasionally occur along 

 the nerves passing from the posterior organ. 



Mastigoteuthis inermis Rancurel 1972 



Vertical Distribution (Figure 28) 



Fifteen specimens were captured during the day 

 at depths of 675 to 870 m; most came from depths of 

 about 700 to 800 m. Ten specimens captured at 

 night came from depths of 255 to 725 m with most 

 specimens being taken between 250 and 450 m. 



200 



400 



Q600 



800 



1000 



-l — I — I — ^ 



-| — I — r 



 4 



' ' 1?l 



20 



30 40 50 60 



MANTLE LENGTH, m m 



90 



Figure 28. — Vertical distribution of Mastigoteuthis inermis. 

 Symbols as in Figure 1. 



Photosensitive Vesicles 



The organs are similar to M. familica except 

 that the central organ is flatter and broadly con- 



tinuous with the posterior organ. The posterior 

 organ extends slightly beyond the insertion of the 

 head retractor muscles and is less elongate. 



Family Joubiniteuthidae 



Jouhiuiteuthis portieri (Joubin 1912) 



Vertical Distribution 



Three specimens, all taken at night, were cap- 

 tured. One (42 mm ML excluding tail) was taken 

 in an oblique tow between the surface and 425 m. 

 A second specimen (64 mm ML) was taken in an 

 opening-closing tow that fished between 480 and 

 550 m, and a third (85 mm ML) was taken in an 

 open tow that fished at 1,125 m. Roper and Young 

 (1975) listed the two known day captures of this 

 species from the Atlantic Ocean as 800 to 900 m 

 and 2,500 m. 



Photosensitive Vesicles (Figure 27 B) 



One set of small organs is present. Each organ 

 consists of a small number of globular vesicles that 

 form a compact organ. Each organ is attached to 

 the posteroventral margin of the optic stalk. 



Family Cranchiidae 



Liocranchia valdiviae (Chun 1906) 



Vertical Distribution (Figure 29) 



Both larvae and adults captured by the Tucker 

 trawl are plotted. IKMT captures have been added 

 where data are weak: specimens >24 mm ML and 

 all specimens captured above 600 m during the 

 day. One hundred fourteen specimens are plotted. 

 Although only a few shallow day captures were 

 made, the vertical distribution pattern is clear: 

 animals between 5 and 15 mm ML predominate in 



599 



