FEMALE GENEEATIVE SYSTEM. 



599 



Fig. 297. 



sions of which are proportioned to the size of the mature ova. It is 

 generally single ; but in some genera, as Loligo and the Octopoda, the 

 canal derived from the ovary soon divides into two (d, e). The walls 

 of the ovigerous duct are thin and membranous until near the external 

 outlet, where they suddenly become thick and glandular, and, in many 

 genera, surrounded with a very large laminated gland (/), through the 

 centre of which the eggs have to pass before they issue from the body. 

 It is the gland last men- 

 tioned that secretes the ex- 

 ternal horny covering of the 

 egg a defence which seems 

 to be deposited in successive 

 layers upon the outer surface 

 of the previously existing 

 chorion, and, when com- 

 pleted, forms a thick flexible 

 case made up of concentric 

 lamellae of a dark-coloured 

 corneous substance. 



(1603.) After extrusion, 

 the ova of the different fa- 

 milies of CEPHALOPODA are 

 found agglutinated and fas- 

 tened together into masses 

 of very diverse appearance. 

 The eggs of the common 

 Cuttle-fish, frequently found 

 upon the shore, are not in- 

 aptly compared by those 

 ignorant of their real nature 

 to a bunch of black grapes, 

 to which, indeed, they bear 

 no very distant resemblance, 

 being generally aggregated 

 in large clusters, and fas- 

 tened by long pedicles either 

 to each other or to some 

 foreign body (fig. 296). 

 The Argonaut carries its 

 eggs, which are compara- 

 tively of small size, securely 

 lodged in the recesses of its 

 shell ; while the ova of the Calamary, encased in numerous long gela- 

 tinous cylinders that conjointly contain many hundreds of eggs, are 

 fixed to various submarine substances, and thus protected from casualties. 



1. Male organs of the Cuttle-fish (Sepia officinalis), 

 seen from before: a, tunic enveloping the testis; 

 b, body of the testicle ; c, convolutions of the vas 

 deferens; e, commencement of the Needhamian canal ; 

 d, pouch of Needham. In fig. 4 the same parts are 

 represented as seen from behind, the testicle being 

 removed in order to show the commencement of the 

 vas deferens. 2 and 3 represent the spermatophores 

 of the same animal, much magnified : a, the external 

 sheath; 6, inner cylinder containing the spermatic 

 fluid; c, the ejaculatory apparatus. In fig. 3 the 

 spermatophore is shown in the act of discharging its 

 contents. 



