BURGESS: FOUR NEW SPECIES OF SQUID KNOPLOTKUTHIS 



on the manus. The ventral row includes a few 

 large curved hooks, the largest hook is about one- 

 fifth larger than the largest arm hook. The hooks 

 have broad bases (Fig. 5D) and fit into shallow 

 depressions on the club. The distal club suckers 

 are arranged in four longitudinal rows (between 

 15 and 18 suckers in each row). The inner rings of 

 these suckers are smooth but are surrounded by 

 an outer ring with broad pegs that can be mis- 

 taken for teeth of the inner ring (Fig. 5C). A few 

 suckers in the distal part of the dactylus are 

 slightly enlarged and form a cluster there at the 

 blunt end of the club. The dorsal or aboral keel is 

 well developed and extends from opposite the 

 third dorsal hook to the blunt end. A smaller 

 semilunar membrane lies on the oral or ventral 

 side of the club. It extends from opposite the 

 distal half of the carpal cluster to opposite the 

 second or third ventral hook. Protective mem- 

 branes are poorly developed but recognizable. 



The integumentary photophores range in size 

 from about 0.2 mm to about 0.4 mm with varying 

 degrees of pigmentation. Some are very dark 

 with small pearl gray centers, others are lighter 

 with varying widths of peripheral pigmentation. 

 Those with very thin dark rings appear palest or 

 almost white. The photophores on the ventral 

 surface of the mantle appear to be distributed at 

 random (Fig. 5A). They are concentrated on the 

 ventral surface except at the tail and gradually 

 become widely scattered toward the dorsal sur- 

 face. A single row extends along each lateral 

 margin of the tail. The free edge of the mantle 

 opening is lined by a transverse row where the 

 photophores are farther separated dorsally. 

 There are no photophores on the fins, or on most 

 of the ventral area of the tail. 



Two rows of photophores separated by a 

 median space are present on the ventral surface 

 of the funnel. A shorter row or patch occurs on 

 each of the lateral margins and a wider strip is 

 found on each of the dorsolateral surfaces of the 

 funnel. 



The distribution of the photophores on the 

 head is rather intricate. A small cluster lies in 

 the apical region of the funnel groove. The 

 ventral midline of the head is not totally clear of 

 light organs, as a few isolated ones may be 

 present. A very short row of three to four 

 photophores in single file on the ventral midline 

 (near the bases of arm IV) splits into two at the 

 fork of the arms; each branch then continues 

 along the ventral aboral edge of arm IV, ending a 

 short distance from the distal tip of the arm. A 



row of photophores begins near the first nuchal 

 fold, follows the curve of the funnel groove, and 

 at a point near the apex of the funnel groove it 

 splits into a wider medial branch and a narrower 

 lateral branch. These branches reunite near the 

 base of arm IV and the combined row proceeds 

 anteriorly along the base of the tentacular sheath 

 to the tip of arm IV. The next lateral row begins 

 anterior to the first nuchal fold, is interrupted by 

 a gap at the window of the eye, continues for a 

 short distance, and divides into two short 

 branches; each branch then extends to the edge 

 of the tentacular sheath independently. A row of 

 single photophores runs along the edge of the 

 tentacular sheath and stops a short distance from 

 the tip of arm IV. The lateralmost row on the 

 head extends from the first nuchal fold along the 

 nuchal crest, then anteriorly to and along the 

 ventral margin of the eyelid, and ends at the 

 ventral edge of the optic sinus. The row begins 

 again on the dorsal edge of the optic sinus, con- 

 tinues along the base of the swimming keel of 

 arm III, and terminates at about one-half the 

 length of the arm. Two or three isolated small 

 photophores occur in the area surrounding the 

 ventral part of the eye opening; one photophore is 

 usually located directly lateral to the window. 



There are nine light organs on the ventral part 

 of the eyeball. The terminal organs are much 

 larger and slightly separated from seven 

 smaller, closely set, light organs (Fig. 51). 



The radular teeth (seven teeth in a series) are 

 long and slender. The outermost lateral teeth are 

 longest while the innermost lateral teeth are 

 shortest. The rachidian tooth has cusps. The 

 three median teeth are almost straight while the 

 two outermost lateral teeth are slightly curved 

 (Fig. 5J). 



The upper mandible (Fig. 5Hi) has a pointed 

 rostrum with very sharp edges and the lower 

 mandible (Fig. 5H 2 ) has three well-developed 

 ribs on the gular plate. 



The gladius is feather shaped and the midrib is 

 low and rounded. The cone is narrow and 

 rounded at the extreme end. The vanes start to 

 broaden at about one-third of the length and 

 reach their greatest width at about half of the 

 length. The lateral edges of the gladius appear 

 slightly thickened when held against a strong 

 light. 



Spermatophores from a male (ML 46 mm) are 

 about 14 mm in total length. The cement body is 

 slightly greater than half the length of the sperm 

 reservoir and has two collars at the oral end (Fig. 



721 



