40 U.S. NATIONAL MUSEUM BULLETIN 291 



The powerful funnel retractor muscle passes posteriorly over the 

 ventrolateral surface of the liver, and in the region dorsal to the 

 branchial heart it flattens out into a broad sheet. Dorsally it merges 

 with the fibers of the liver sheath and attaches to the shell-sac along 

 the edge of the rhachis and vane of the gladius. The funnel retractor 

 sheath attaches to the lateral wall of the mantle. 



The vane of the gladius arises from the rhachis at a point in line 

 with the branchial hearts. The vane broadens gradually posteriorly 

 and curves ventrolaterally with the mantle wall. The visceral dome 

 and the visceral-pericardial coelom lie directly ventral to the vane and 

 are attached to the shell-sac with w^eak connective tissue. The relation- 

 ship of the posterior end of the gladius with the tip of the mantle is 

 difficult to ascertain, because the mantle tip always seems to be vio- 

 lently contracted. The contractions push the vane of the gladius an- 

 teriorly and ventrally in a series of irregular folds. 



The rhachis of the gladius is very long and narrow (pi. 2g). The 

 free portion of the rhachis accounts for over half the length of the 

 gladius. Tlie lateral edges of the rhachis are strong, straight, cylindri- 

 cal rods that are joined dorsomedially by a concave strip. A deep 

 groove lies between the lateral rods; anteriorly the groove of the 

 rhachis holds portions of the muscles of the collar and liver-sheath 

 that are attached to the shell-sac. In the posterior half of the gladius 

 the rods of the rhachis converge and taper gradually until they disap- 

 pear in the posterior end of the vane. 



The vane is a thin, blade-shaped structure that arises at about the 

 midpoint of the gladius. It broadens gradually to its widest point 

 posteriorly then quickly terminates in a bluntly rounded tip. No conus 

 is present. The anterior portion of the vane is nearly flat, but the 

 broader posterior section is deeply concave, conforming with the shape 

 of the tapering mantle. Considerable variation exists in the shape of 

 the vane. 



The spermatophores (pi. 2h) are 4.5-7 mm in total length, depend- 

 ing upon the size of the male. The proportions of the components, 

 however, remain relatively constant. The sperm mass occupies about 

 68-72% of the total length; the cement body makes up 6-8% of the 

 length, and the ejaculatory apparatus occupies the remaining 20-25%. 

 The base of the ejaculatory apparatus is goblet-shaped; the basal sec- 

 tion is a thickened collar that fuses with the cigar-shaped cement body. 



No hectocotylus exists. 



HoLOTYPE. — British Museum (Natural History) ; BM 1890, 1.24.15. 



Type locality. — Between Prince Edward Island and the Crozets 

 Islands at 46°16'S 48°27'E. HMS Challenger, 30 December 1873. 



Distribution. — Bathypelagic in the Southern Ocean and in the pro- 



