26O S. STILLMAN BERRY. 



more flaring mantle possessed by all three Madeiran examples is 

 doubtless but an incident of the mechanics of their preservation. 

 The same is doubtless true of the apparent great number of 

 chromatophores resulting in the consequent darker color of these 

 specimens. The greater conspicuousness of the chromatophores 

 seems to carry a concomitant accentuation of the photophores so 

 that at first sight they appear much more numerous than in the 

 Messina specimen. The attempt to count the photophores in 

 corresponding areas, however, has not led to proof of any actual 

 critical difference in their number. 



The male indeed does show a few slight differences in the 

 structure of its beautifully preserved hectocotylus, especially in 

 the fact that the tip of the modified arm is so produced and 

 attenuated beyond the curious fleshy folds which are a feature of 

 the distal part of this arm in the present species, and regarding 

 the exact function of which we are still quite in the dark except 

 that there seems good reason to believe that they may serve in 

 some fashion or other in the manipulation and fixation of the 

 spermatophores. 



This male and one of the females show but three hooks on each 

 tentacle club. The other female has three hooks and a possible 

 remnant of a more minute proximal one on the left club, while the 

 right club bears four hooks in agreement with both clubs of the 

 Messina specimen. These seem but normal variations. I have 

 noticed no record of any specimens with clubs bearing less than 

 two nor more than four hooks. 



A certain degree of sexual dimorphism is, as already noted, 

 indicated by the present specimens, but it is not conspicuous, 

 being chiefly manifested by the somewhat smaller body and fins 

 of the male. The differences noted appear both absolute and 

 relative. The fins are almost equally wide in proportion to 

 mantle length in both males and females, but in the former they 

 are relatively somewhat shorter, giving an index of about 60 as 

 against 66 in the females. The arms of the male on the other 

 hand are somewhat longer in relation to the body than those of 

 the female. 



As was discovered by Steenstrup ('80, p. no), the spermato- 

 phores become attached in a rosette-like cluster to the inner 



