74 U.S. NATIONAL MUSEUM BULLETEST 291 



with 0, 1, 2 and none at all with 1, 3. Antarctic ahyssicola is not rep- 

 resented by any specimens that have 4 or 5 suckers on their lappets; 

 only one specimen had as many as 3 suckers. Therefore, hacidifera 

 appears to possess a greater number of suckers on buccal lappets than 

 does ahyssicola from Antarctic waters. 



The preceding discussion about the suckers on the buccal lappets 

 of Bathyteuthis points out that variability exists in this character 

 not only between species and populations but also between individuals 

 of the same population. The general trend is toward an increase in 

 numbers of suckers with increase in size and for populations in lower 

 latitudes to have a significantly greater number of suckers on the 

 lappets. B. ahyssicola from the Antarctic exhibits the least tendency 

 toward increased numbers of buccal suckers with increased size, and 

 in addition very seldom ever has more than two suckers on any single 

 lappet and often has no buccal suckers at all. In contrast, larger speci- 

 mens of ahyssicola from the Atlantic may have combinations of 4, 5, 

 6, and 7 lappet suckers, and the smallest specimens available have at 

 least some suckers. In the eastern Pacific populations of ahyssicola and 

 hacidifera the data are less complete, but the trend is indicated. 



Significance of Buccal Suckers 



Possession of suckers on the buccal lappets apparently is a special- 

 ization to an environmental pressure and not a primitive character as 

 suggested by Naef ; the character is variable enough to meet particular 

 narrower demands of the environment. It is suggested here that the 

 specialization is an adaptation associated with the acquisition of a par- 

 ticular type of food in the deep sea habitat of Bathyteuthis. 



Contrary to Chun's suggestion (1910), I feel that characters asso- 

 ciated with the digestive system of oegopsids (other than basic struc- 

 tures) are poorly suited for use in determining relationships of fam- 

 ilies. Structures and procedures for obtaining food would seem to be 

 necessarily susceptible to adaptation to various environmental require- 

 ments. Recent cephalopods show a wide range of adaptations of the 

 mechanical means for obtaining particular foods and of the physio- 

 logical processes required for handling these special foods. Buccal 

 suckers may be one of these adaptations. 



Bathyteuthis is a true deep-sea cephalopod, exhibiting a number of 

 modifications to the deep-sea habitat. As such, it must be derived 

 from a shallower living form. If suckers on the buccal lappets do re- 

 flect the primitive condition in the Oegopsida as suggested by Naef, 

 it seems more probable that they would be found on a generalized, 

 shallow-living form rather than on a specialized, deep-sea form. They 

 are not found in shallow-water forms. The possession of suckers on 



