FISHERY BULLETIN: VOL. 80. NO. 4 



lapping hood which conceals a few of the suckers 

 at the tip. The aboral keel is also narrow and 

 extends from opposite the second hook to the 

 lateral side of the hooded tip. Protective mem- 

 branes are not developed on either side. 



The photophores range in size from 0.2 to 0.4 

 mm. The dark or light appearance of each 

 photophore is caused by the extent of pigmenta- 

 tion. The majority of the small ones are white 

 owing to pigmentation confined only to the 

 periphery of the photophores. The photophore 

 pattern of the mantle is distinctive. It can be 

 described briefly as the combined effect of about 

 six ill-defined longitudinal rows and four oblique 

 rows to produce a netlike or reticulated pattern 

 (Fig. 6A). The photophores are scattered irregu- 

 larly in the posterior region of the mantle, except 

 on the tail where a single row extends on each 

 side to the tip of the tail. The ventral area of the 

 saccate tail lacks photophores. A single trans- 

 verse row in which the photophores are farther 

 apart dorsally lies along the anterior edge of the 

 mantle. A few small photophores are distributed 

 on the dorsal surface of the mantle. The fins lack 

 photophores. 



Two longitudinal rows, separated by a midline 

 space, occur on the ventral surface of the funnel. 

 A short row (connected to the ventral row pos- 

 teriorly) is located on each side of the funnel and 

 a long row of photophores is found on the dorso- 

 lateral side, close to each bridle. 



The photophore pattern on the ventral side of 

 the head is observed best in smaller specimens. 

 Two clusters, separated by a narrow midline 

 space, lie in the apex of the funnel groove. A clear 

 space occupies the ventral midline of the head. 

 Eight main rows of photophores (four rows on 

 each side of the midline space) are present. The 

 first or most medial row begins at the posterior 

 end of the funnel groove, extends anteriorly to 

 the ventral aboral side of arm IV, and reaches 

 almost to the tip of this arm. The second row 

 branches out from the first row near the apex of 

 the funnel groove, extends parallel to the first 

 row and joins it at a point near the base of arm 

 IV, at about the same level as the anterior 

 margin of the eye. At the base of arm IV the 

 width of the second row is increased by addi- 

 tional photophores, and as the row continues 

 along the base of the tentacular sheath distally it 

 is gradually reduced to a single series of photo- 

 phores which reaches the tip of the arm. A very 

 short row or cluster of photophores occurs be- 

 tween the first and second rows at a short 



distance beyond the base of arm IV, but in older 

 individuals this short row tends to lie closer to the 

 second row and may be difficult to distinguish. 

 The third lateral row extends from opposite the 

 first nuchal fold anteriorly (interrupted by a gap 

 at the window of the eye) to the base of arm IV 

 where it merges with the second row. A branch 

 continues further along the edge of the tentacu- 

 lar sheath almost to the tip of arm IV. The fourth 

 or most lateral row extends from the second 

 nuchal fold to the posterior margin of the eye and 

 passes along the edge of the ventral eyelid to the 

 ventral edge of the optic sinus. The row begins 

 again on the dorsal edge of the optic sinus and 

 continues along the base of the swimming keel of 

 arm III to a short distance from the tip. An 

 arclike row of small white photophores, spaced 

 widely, lies along the ventral region of the eye be- 

 tween the third and fourth rows of photophores. 



Nine light organs, arranged in a single row, 

 are present on the ventral side of the eyeball. The 

 terminal organs are much larger than the seven, 

 closely spaced, interior light organs and are set 

 apart from them. The interior organs are not of 

 uniform size (Fig. 6J). 



The seven radular teeth are blunt and slightly 

 curved. The rachidian has low lateral cusps (Fig. 

 6H). 



The mandibles are strong; the rostrum of the 

 upper mandible is pointed and the edges are 

 sharp (Fig. 6G1). The gular plate of the lower 

 mandible is reinforced by three stout ribs (Fig. 

 6G 2 ). At ML 45 mm the wings of both halves are 

 already well pigmented. 



The gladius is thin with a low rounded midrib. 

 The vanes are narrow and widest at about the 

 middle. The cone is thin-walled and as wide and 

 rounded as the anterior end of the gladius. 



The spermatophores are large. The cement 

 gland has a large swelling at the aboral end (Fig. 

 6K). The aboral end of the spiral filament, 

 anterior to the cement gland, is plain except for 

 some longitudinal ridges. Two or three spiral 

 turns behind the cap are present. Measurements 

 from two specimens are given below: 



Length (mm) 



726 



