94 JOURNAL OF CONCHOLOGY, VOL. 9, NO. 3, JULY, 1898. 



them dropped, as if aware that the distance (6 to 7 feet) was too great 

 for safety, but first one ascended the thread while the other remained 

 stationary, and then the other followed, leaving the thread dangling. 

 After an absence of 10 minutes I found that the thread had dis- 

 appeared. It certainly had not dropped, so I concluded one or both 

 had returned and eaten it. 



What power of sight these creatures possess I cannot say, but the 

 strong light of a bull's-eye lantern flashed suddenly upon them and 

 close to them never causes them to withdraw their tentacles or affect 

 their composure in any way, and this not only when they are in a 

 state of sexual excitement, but when they are roving about solitary or 

 feeding. 



Being anxious to determine the identity of the organs extruded, I 

 severed the parts in question from a paired couple and submitted them 

 and the animals to Mr. W. M. Webb, F.L.S., for dissection and to 

 him I am indebted for the following interesting particulars. 



" One of the severed structures resolved itself into the half- 

 evaginated penis, bearing at its posterior end the retractor muscle cut 

 off short and a considerable portion of the vas deferens. The second 

 penis was completely extruded, showing the peculiar frill on one side of 

 its tube, down the interior of which tube the vas deferens was traced, 

 though the retractor muscle was not discovered." 



Free oviduct. /J5^ Uterus, A Forming 



A/ / Attached oviduct, v- common 



s-.\ £j / Sperm duct. \ duct. 



Spermatheca. J- J \Jy/ Vas deferens. 



\Ys- y 'H '' /~N >#-- Retractor muscle. 



Position of y\\ 11 ,'' [ \ // 



genital opening. \ \ \\»' \ W 



\ \ *-^ .-/. Penis. 



Mr. Webb also kindly furnished me with the annexed rough dia- 

 gram to illustrate his further remarks, which are as follows : 



"A glance at the unravelled genitalia brings out the fact that there 

 is practically no vagina, the penis, oviduct and spermathecal duct 

 meeting almost at the same point, just within the genital opening. 

 The shortness of the sper??iathecal duct and the position of its opening 

 also point to the filling of the spermatheca from the outside of the 

 animal ; and one would say that the use of the penis is to convey the 

 sperm cells to and not into the female orifice, its frill being deve- 

 loped for the purpose of holding them during the act of passing them 

 over to another individual." 



The only detailed description of this interesting method of pairing 

 is in Ferussac's scarce work, " Histoire naturelle generale et par- 



