FISHERY BULLETIN: VOL. 76. NO. 3 



Family Cycloteuthidae 



Cyclotenthis serventy i ]ouh'\n 1919 



Vertical Distribution (Figure 18B) 



Three specimens were taken between 750 and 

 800 m during the day. The single night capture 

 came from an IKMT that fished at 750 m; however, 

 the specimen may be a contaminant, as Roper and 

 Young (1975) listed most of the known night cap- 

 tures of this species from the Atlantic in the upper 

 200 m. 



Photosensitive Vesicles (Figure 19B) 



The arrangement of vesicles is complex. On each 

 side of the head, two flattened lobes are located 

 ventral and lateral to the central brain in approx- 

 imately the positions of the anteroventral and 

 midventral lobes of the Abraliinae . The midven- 

 tral lobe sometimes connects to a complex series of 

 vesicles extending dorsally. These latter vesicles 

 consist of two series: a more posterior series of 

 irregular flattened vesicles lying on the postero- 

 medial surface of the optic lobe; and a thicker, 

 irregular, and rather extensive series of vesicles 

 lying between the optic lobe and peduncle com- 

 plex. These two series interconnect at various 

 points. At about the level of the optic gland, a thin 

 dorsal organ extends up the medial wall of each 

 optic lobe and onto its anterodorsal surface. This 

 terminal portion gradually widens but remains 

 thin. 



D is CO te u tb is la ciu iosa 

 Young and Roper 1969 



Vertical Distribution (Figure 18B) 



Five specimens were taken during the day be- 

 tween 400 and 700 m, although the shallowest 



capture came from a tow that dipped briefly to 480 

 m. At night, a single specimen was taken in an 

 oblique tow from the surface to 350 m. 



Photosensitive Vesicles (Figure 20A) 



The arrangement of vesicles is complex. A 

 broad, flat, irregular ventral lobe is located be- 

 tween the posteroventral surface of the optic lobe 

 and the cephalic cartilage, and opposite the inser- 

 tion of the head retractor muscles. The broad, flat 

 nerve passing to this lobe bears a series of often 

 isolated vesicles or irregular strands of vesicles 

 which, nearer the brain, join a single, somewhat 

 flattened cord. This central organ extends dorsally 

 and expands somewhat near the optic gland. Al- 

 though this general pattern holds between speci- 

 mens, considerable variation in the size of various 

 parts of the central organ occurs. 



Family Brachioteuthidae 



Brachioteutbis sp. 



Vertical Distribution (Figure 21) 



Three specimens were captured during the day 

 between 800 and 975 m. Only the mantle of a 

 fourth specimen was present in a day tow at 450 m. 

 The previous tow fished at 900 m and captured one 

 of the other three specimens; the shallow capture 

 is probably a contaminant. Seven of the eight 

 specimens captured at night were taken between 

 30 and 235 m. The remaining specimen was taken 

 at 1,125 m in an open tow and was a gravid female 

 with sperm masses embedded in the buccal mem- 

 brane. 



Photosensitive Vesicles (Figure 20B) 



A single set of organs is present. Each organ is 

 situated on the posterior margin of the optic stalk 



Figure 20. — A. Photosensitive vesicles of Discoteuthis 

 laciniosa. B. Photosensitive vesicles oi Brachioteutbis sp. 

 Abbreviations as in Figure 2. 



