o/ Nautilus Pompilius. 71 



I consider this covering of the spermophore as one of the 

 most remarkable peculiarities which the investigation of the 

 male Nautilus has revealed to me. The enclosing of the 

 spermophores in the bladder must of necessity have occurred 

 after they had passed through the penis. Even if I had not 

 actually met with spermophores in the canal of the penis, as 

 stated above (p. 70), which were not yet included in such a 

 bladder, still the considerable size of the bladder would have 

 precluded the possibility of a passage through that canal. The 

 membranes of this bladder are thus secreted on the outside of 

 the visceral cavity. Where and by what organs is the secretion 

 effected ? To this question I can only answer by conjecture. 

 In the branchial sac nothing is seen that can perform the secre- 

 tion. But on the other principal portion of the body are two 

 organs which may be noticed here. In the first place, it may be 

 supposed that the numerous folds of the organ situated behind 

 the lower jaw below the oesophagus (p. 64) serve for secreting. 

 In the second place, the round glandular disk deserves con- 

 sideration, which is situated on the outer surface of the spadix. 

 Whilst it is uncertain whether the first-named organ discharges 

 a secreting office, there can be no doubt respecting such a func- 

 tion in the second ; but it does not follow from this that the 

 secretion which occurs in the said disk is exactly for the forma- 

 tion of the bladder which encloses the spermophore. Had I been 

 fortunate enough to encounter in any specimen spermophores 

 on the road from the branchial sac to the dorsal surface of the 

 animal, then this matter might have been susceptible of a more 

 accurate determination. 



I am not in a condition to show how the bladder with spermo- 

 phores is expelled from the shell of the male at a later period. A 

 real copulation cannot take place : not only is the penis situated 

 too deeply in the mantle for this, and too short, but moreover 

 the enveloping of the spermophores shows that the expulsion of 

 the sperma by the penis has preceded by some time the impreg- 

 nation. I think I cannot be wrong in regarding the enclosing 

 of the spermophores as a means of preserving the sperma for a 

 time from the effect of sea-water until it has arrived at the place 

 of its destination, the branchial sac of the female Nautilus. 



We will, in conclusion, treat of the structure of the spermato- 

 phores* or spermophores, as far as they can be investigated in spe- 

 cimens which have been long kept in spirit. It is well known that 

 the sperma of Cephalopods is enclosed in singular bodies of very 

 large size, which Swammerdam first described in Sepia officinalis 

 as ^^witte en teere pennekens, die zich in water bewegen en 



* Duvernoy changed this name into sperraaphores ; by a slight modi- 

 fication, after the remark of a celebrated Hellenist, we prefer to write 

 spermophores. 



