68 U.S. NATIONAL MUSEUM BULLETIN 291 



however, may be too close to the limits of the range of variation of fin 

 length and width for abyssicola. and because of the small sample size 

 of hacidifera^ may not be significant. 



Differences in proportions are noted with the lengths of the tentacles 

 and especially of the clubs ; the club is 28-30% longer in hacidifera than 

 the average for ahyssicola of the same mantle lengths. Therefore, both 

 species exhibit nearly the same characteristics of proportional growth. 



Key to the species of Bathyteuthis 



1. Protective membranes on arms low to well developed, fleshy, with straight 



to gently scalloped borders ; trabeculae not free, enlarged, or elongate ... 2 



Protective membranes reduced or lacking; trabeculae free, elongate, rodlike; 



arm suckers numerous, rings with 18-34 protuberances; gills long, broad. 



B. hacidifera Roper, 1968 



2. Arm suckers relatively few, rings with 8-18 protuberances; arms short, blunt; 



gir.s short, narrow B. ahyssicola Hoyle, 1885 



Arm suckers extremely numerous, rings with 10-14 protuberances; arms long, 

 attenuate; gills long, broad B. herryi Roper, 1968 



Geographical Variation in Bathyteuthis; Interspecific 

 and Intraspecific Variation of Taxonomically 

 Important Characters 



Buccal Suckers 



The Bathyteuthidae and the Ctenopterygidae are the only families 

 of Oegopsida known to possess suckers on the oral surface of the lap- 

 pets of the buccal membrane. It is primarily (though not exclusively) 

 because of the possession of this character that Bathyteuthis and 

 Ctenopteryx had been brought together in the past under the Bathy- 

 teuthidae. Both Naef (1923) and Grimpe (1925) considered that the 

 buccal suckers, four rows of arm suckers, and many rows of club 

 suckers are primitive characters within the Oegopsida, and they 

 placed the Bathyteuthidae first in the suborder immediately adjacent 

 to the Myopsida. 



The large number of specimens of Bathyteuthis available in this 

 study makes it possible to examine the occurrence of buccal suckers 

 over the geographic ranges of the species and to determine the value 

 of these suckers as a taxonomic character at the species level. 



1. Bathyteuthis ahyssicola — Antarctic 



B. ahyssicola from the Antarctic exhibits a variety of combinations 

 of suckers on each of the buccal lappets. An individual may have 0, 1, 



2, or 3 suckers on each lappet. Very seldom do all seven lappets of 

 an individual bear the same number of suckers, except when suckers 

 occur. For instance, a specimen may have suckers on two lappets, 1 



