?6 MULLER ON THE MALE OF 



and indeed in a peculiar manner, which reminds one of the 

 process of eversion of the spermatophora of other Cepha- 

 lopoda described by Milne-Edwards (Annales d. Sc. Naturelles* 

 1842). 



From the preceding facts I will merely draw the conclusion, 

 that the sexual organs in Hectocotylus Tremoctopodis are not only 

 more complicated than in Hectocotylus Argonaut a, but that dif- 

 ferent stages in their development occur, although the Hectoco- 

 tylus possesses in general the same form as that with which we 

 are already acquainted. Our knowledge of this Hectocotylus is 

 too imperfect to enable us to give a general interpretation of the 

 generative organs. But its structure and the analogy with the 

 Hectocotylus of the Argonaut lead to the supposition that the 

 vesicle which contains the seminal coil is not the testis, but a 

 seminal receptacle, although the mode in which the semen makes 

 its way, and the place of its origin are less demonstrable than in 

 the Hectocotylus of the Argonaut. 



Next to the generative apparatus, the most striking features 

 in Hectocotylus Tremoctopodis are the numerous villi on each 

 side of the back, which Kolliker has with great probability 

 called gills *. 



In the living Hectocotylus the single villi are contractile, ap- 

 parently in consequence of the fibres which form a meshwork 

 in their interior. Independently of this movement of their sub- 

 stance, a considerable rhythmical contraction may be observed 

 in the efferent (venous) part of the very rich and frequently 

 anastomosing vascular network which lies in each villus, and 

 which passes from the finer to the coarser vessels, as was stated 

 above to be the case in the Hectocotylus Argonautce and in the 

 Cephalopoda in general. In one instance there were twenty-two 

 contractions in ten minutes. 



Since these branchial villi might occur in different individuals 

 in different degrees of contraction, the determination of their 

 size in different individuals appeared to be a matter of some 

 interest. For this purpose the largest group of villi in each of 

 several specimens preserved in spirit was selected. When they 

 were very much developed, their length was about 0-6-1-2 of a 



* Do these in any way subs.erve nutrition within the mantle of the female? 

 (see Von Sicbohl, /. c. p. 389). 



