FISHERY BULLETIN: VOL, 76. NO. 3 



elongate vesicles that are most numerous at its 

 ventral end. The central organ consists of a few 

 small, flat, elongate vesicles located on the dorsal 

 surface of the optic stalk. The vesicles of the dorsal 

 organ are scattered along a broad arching nerve 

 that extends from the peduncle lobe dorsally then 

 anteriorly along the dorsomedial margin of the 

 optic lobe. The vesicles are flat and irregularly 

 shaped. 



Hyalotenthis pelagicHS (Bosc 1802) 



Vertical Distribution 



The single specimen captured was taken in an 

 opening-closing tow between 1,700 and 2,200 m 

 during the day. The specimen was a gravid female: 

 the ovary was packed with mature eggs, the nida- 

 mental and oviducal glands were greatly en- 

 larged, and numerous discharged spermatophores 

 were attached to the lips surrounding the mouth. 

 Specimens in similar condition as well as imma- 

 ture specimens have been captured frequently at a 

 depth of about 100 m at night by the National 

 Marine Fisheries Service, NOAA, in Honolulu 

 using a large Cobb trawl. Hyaloteuthis pelagicus 

 typically avoids our midwater trawls. The single 

 day capture demonstrates that this species is cap- 

 able of descending to great depths. Unfortunately, 

 nothing is known of its normal day habitat. 



Photosensitive Vesicles (Figure IIB) 



Three sets of organs similar to those of S. 

 oualaniensis are present. A small central organ 

 lies just dorsal to the optic stalk and consists of a 

 relatively small number of rather large vesicles. 

 Each dorsal organ lies above the dorsomedial side 

 of the optic lobe and is a large, compact triangular 

 organ with irregularly shaped vesicles. The ven- 

 tral organ is a flat, compact, oval organ which 

 abuts against the cephalic cartilage above the lat- 

 eral base of the funnel. 



Nototodarus hawaiiensis (Berry 1912) 

 Vertical Distribution 



No specimens have been taken in our midwater 

 trawls; however, 63 specimens were captured in 

 40-ft shrimp trawls by the National Marine 

 Fisheries Service. Specimens captured during the 

 day came from depths of 230 to 710 m, although 



only a single capture was made below 420 m. 

 Night captures range from 110 to 410 m. During 

 the late summer and early fall, this species is 

 commonly taken by dip net or near-surface jig at 

 night off the island of Hawaii. 



Photosensitive Vesicles (Figure 12A) 



Three sets of organs are present similar to those 

 in S. oualaniensis and H. pelagicus. The central 

 organ is slightly larger than that of S. oualanien- 

 sis but is positioned similarly. The dorsal organ 

 consists of a flat strip of vesicles that extends from 

 the central organ dorsally to the cephalic carti- 

 lage. The margins of this organ are irregular, and 

 thin strings of vesicles extend away from the 

 organ at various places. Where the dorsal organ 

 connects with the central organ, the two can be 

 distinguished by the sizes of their individual vesi- 

 cles: the small central organ consists of relatively 

 few large vesicles, while the dorsal organ consists 

 of numerous small vesicles. The ventral organ is 

 compact, flattened, and somewhat club-shaped. It 

 occupies about the same position as the corres- 

 ponding organs in S. oualaniensis and H. 

 pelagicus. 



D PV 



D.PV 



V. PV 



VPV 



Figure 12. — A. Photosensitive vesicles of Nototodarus 

 hawaiiensis. B. Photosensitive vesicles of Histioteuthis 

 dofleini. Abbreviations as in Figure 2. 



Family Histioteuthidae 

 Histiotenthis dofleini (Pfeffer 1912) 



Vertical Distribution (Figure 13) 



The vertical distribution of this species has been 

 discussed by Young (1975c). The vertical range is 

 375 to 850 m during the day; over 80^7^ of the 

 captures came from depths of 500 to 700 m. At 



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