178 MEMOIRS OF THE NATIONAL ACADEMY OF SCIENCES. 



The second question is, How are the spermatophores conveyed from the penis to the labial 

 tentacles? The latter are widely removed from the penis, beside being- inside the cephalic sheath. 

 One course has suggested itself as possible. The spermatophore being discharged from the penis 

 may be carried through the funnel to its tip. It will be remembered that the tip of the funnel 

 lies in a groove on the ventral side of the cephalic sheath, and that the cephalic sheath is deeply 

 notched just above the tip of the funnel, so that the latter projects slightly beyond the posterior 

 edge of the notch. It may be that when the spermatophore reaches the tip of the funnel it is 

 grasped by some of the tentacles, either digital or labial, and conveyed by them to its final 

 position among the dorsal tentacles of the superior labial group. Van dek Hoeven's organ lies 

 just back of the ventral notch, and if it plays any part in the formation of the sac of the spermato- 

 phore, the spermatophore may remain for a time in the depression into which the organ opens. 

 Possibly the tip of the funnel may be turned upward and the spermatophore forced inside the 

 cephalic sheath by a jet of water. I do not wish this suggestion to be interpreted as my theory 

 of how the spermatophore travels to the labial tentacles from the penis. It is only a suggestion, 

 which may be far from the truth, but which, arising from the anatomical relations of the various 

 parts concerned, I think it can do no harm to publish. Such a transfer would, however, involve 

 an active coordination of different parts which is quite unique among Mollusca in processes 

 accessory to fertilization. 



It is noticeable that the spermatophores are not found in any connection with the spadix, 

 which has been frequently considered analogous to the hectocotylized arm of the Dibranchiata. 

 What the role of this organ is, is as much a mystery as ever. Its large size and complicated 

 structure indicate that its function is important, and that there may be several minor processes 

 which cooperate to perform the function for which the structure has been developed. 



It has been suggested that the spadix is thrust into the mantle cavity of the female during 

 copulation. Evidently this is the idea of Vayssiere, who suggests that the function of the large, 

 firm, and pointed first cirrus of the spadix is to facilitate the introduction of the spadix into the 

 mantle chamber of the female. The fourth cirrus on account of its small size and position may 

 have little share in the functions of the spadix. Vayssiere considers that the active parts in 

 transferring the spermatophore to the female are the second and third cirri. The latter is especially 

 fitted for this, and he suggests that the spermatozoa are carried in the crypts after the destruction 

 of their protective envelopes, and being ejected from these by a momentary turgescence of the 

 tongues are deposited at the orifice of the oviduct. 



The second and third cirri of the spadix are evidently capable of considerable extension, and 

 are probably very active portions of the organ in doing whatever work for which it is designed, 

 but there is scarcely any reason to suppose that the spadix, and especially the third cirrus thereof, 

 act as Vayssiere lias suggested. For we have alreadj T noticed that the female frequently carries 

 a spermatophore coiled upon the surface of the lamellated region inside the edges of the ventral 

 notch of the cephalic sheath. It seems probable that the spermatophore is transferred from the 

 male direct to this place. It is quite remarkable that the sac which surrounds the spermatophore 

 when among the tentacles of the male has already been lost, the spermatophore lying naked, coiled 

 upon the surface of the receiving apparatus of the female. 



As the spermatophore is still intact, the third cirrus of the spadix certainly has no such use 

 as Vayssiere suggests. Indeed, it seems strange that so complicated an organ as the spadix 

 should have been required for so simple an operation as placing the spermatophore inside the 

 cephalic sheath of the female. The female Loligo carries spermatophores upon the buccal 

 membrane, but in the case of Loligo /» alii there is not the slightest trace of a hectocotylized arm 

 or other specialized apparatus for depositing the spermatophores upon the buccal membrane of the 

 female. It seems quite possible that the spadix of Nautilus may not function at all in the 

 transfer, it being entirely accomplished by the superior labial tentacles. Or possibly the spadix 

 serves to push aside the tentacles of the female and allow of the deposition of the spermatophore 

 within them. 



The development of the spadix in the adult male alone indicates that it is an accessory repro- 

 ductive organ, but of its function we are absolutely ignorant. 



