19 



to any object, the extensor relaxes, the sphincter 

 contracts, and the massive muscular base of the inner 

 chamber is elevated to meet the sphincter. Thus we have 

 a shallow flattened disc-like surface pressed closely 

 against the object to be held. Now the extensor contracts 

 and the sphincter relaxes a little, and the floor of the 

 inner chamber is drawn away from the object, producing 

 the desired vacuum. 



All Cephalopods have power to regenerate injured 

 arms. Frequently specimens of Eledone have been seen 

 with several arms in process of regeneration. When an 

 arm is first injured, it is curled up spirally towards the 

 mouth so as to protect the injured part. 



'clrpr. 



gr. a. 



Fig. IV.— (a) licctocotyliscd arm and (6) ordinary aim of male 

 E. aldrovancli. x 2. 



Hectocotylisation.— The third right arm of the male 

 Eledone is hectoeotylised, i.e., it is modified for the 

 purpose of transferring the spermatophores expelled from 

 the anterior opening of the funnel into the oviduct of the 

 female. As no male E. cirrosa could be obtained, Text 

 fig. IV a, shows the hectoeotylised arm of a young- 

 male E. aldrovandi, which is very similar. Some 

 Tephalopods have an autotomous hectoeotylised arm, e.g. 

 Argonauta and TremoctojJus, and in these hectocotylisa- 

 tion reaches its extreme state of specialisation. 

 Spermatophores having been expelled from the funnel of 



