YOUNG: VERTICAL DISTRIBUTION AND PHOTOSENSITIVE VESICLES 



40 50 60 70 



MANTLE LE NGTH.m m 



Figure 21. — Vertical distribution otBrachioteuthis sp. Symbols 

 as in Figure 1. 



and extends from the optic gland ventrally and 

 laterally to the level of the ventral surface of the 

 central brain. Each organ consists of numerous 

 small tightly packed vesicles. 



Family Chiroteuthidae 



Chiroteuthis sp. 



Vertical Distribution (Figure 22A) 



Three specimens captured during the day were 

 taken between 700 and 800 m. At night, eight 

 specimens were captured between 15 and 750 m; 

 however, six of these came from the upper 200 m. 



Photosensitive Vesicles (Figure 23A) 



One set of small organs is present. Each organ 

 arises on the posterior margin of the optic stalk 

 and extends from the optic gland ventrally to 

 about the level of the ventral surface of the central 

 brain. The organ consists of many small, tightly 

 packed vesicles. Growth of the vesicles from the 

 juvenile stage on is allometric. While the size of 

 each organ increases slightly, the number of com- 

 ponent vesicles decreases. 



Figure 23. — A. Photosensitive vesicles oi Chiroteuthis sp. B. 

 Photosensitive vesicles of Chiroteuthidae gen. sp. Abbreviations 

 as in Figure 2. 



Chtroteuthis picteti Joubin 1894 



Vertical distribution (Figure 22A) 



Two day captures were made between 750 and 

 950 m, and a single night capture was made at 

 175 m. 



Photosensitive Vesicles 



200 - 



400 - 



40 60 to 100 



MANTLE LENGTH .on 



to 100 uo 



MANTLE LENGTH, «a 



Figure 22. — A. Vertical distribution oiChiroteuthis sp. (circles) 

 and Chiroteuthis picteti (triangles). B. Vertical distribution of 

 Chiroteuthidae gen. sp. Symbols as in Figure 1. 



The organs are essentially the same as in large 

 specimens of Chiroteuthis sp. A. 



Chiroteuthidae Gen. Sp. 



Vertical Distribution (Figure 22B) 



All eight specimens of this species were cap- 

 tured during the day between 775 and 975 m. 



Photosensitive Vesicles (Figure 23B) 



The organs are very similar to those in 

 Chiroteuthis spp. One set is present. Each organ 

 consists of small circular vesicles tightly packed 

 into a well-defined organ that attaches to the pos- 

 teroventral margin of the optic stalk. 



597 



