44 SKXI'AI, nl!(i.\NS. 



those of Loligo that he li:is examined, were round to carry a 

 greater or less quantity of spermatophores around their mouth. 



Steenstrup lias shown ( Ann.. M<I. \a(. ///*/., 1> Ber., xx. lXf>7) 

 that whilst tlie octopods (which alone arc known to lose tlicir 

 'opulatoiy arm) possess in the highest decree the power to 

 reproduce mutilated members; the decapods, on the contrary, are 

 not able to remedy such losses by a new growth ; and this is nil- 

 other cogent reason lor believing that the process of fecundation 

 is entirely different in the two groups. Stecnstrup slates that 

 the hectocotylixed arms, so far as he can ascertain, present no 

 changes at the season of copulation, that they present the same 

 features in small as in large individuals; and he assumes that 

 when the young male leaves the egg it is already furnished with 

 the hectocotylized arm proper to its species. 



r>raun has supposed the aptychi to be the shells of the males 

 of Ammonites, instead of opercula ; this would explain why they 

 are so often found at the base of the first chamber of Am- 

 monites. 



It is also possible that the fragment of a mollusk found by 

 Quoy and (iaimard at the Celebes Islands (An/t. ,SV. \tt/.. 

 470, 1<S,30) may be the llectocotylus of the long-sought male of 

 Nau t ii n* i >n mpilius. 



M. I'ssow observes that the spawning time of Argonauta I 

 from May to August; of Loligo, Sepiola and Ommast .replies. 

 from March to June ; but he has obtained mature ova of Sepia 

 in Naples almost, all the year round, except in August. USSOW, 

 " Dexclopment of Ciqihalopoda." Ann. Mtuj. A'. //., \ st-r.. xv. 

 L875. 



I have ligurecl a few Inrnis of egg-clusters ( I'l. 1 U, -JO. 22) ; 

 Unfortunately the eggs of the Nautilus are not, known, so that 

 oui 1 knowledge i> confined to the dibranchiates. Of these the 

 most curious is the Argonaut, the elegant shelly structure of 

 which originates from the expanded dorsal arms of tin- female 

 which cover its sides and form the only attachment of the animal 

 to it. In the unoccupied hollow of the spire are attached the 

 minute clustered eggs, and its special function appears to be for 

 their protection during development. Kach egg is separately 

 enclosed in a rounded shell, which is furnished with a hng. thin 



