238 



CEPHALOPODA. 



female of Rossia (according to the verbal statements of F. C. v. Maerenthal) 

 there is a well-marked area near the mouth of the oviduct within which the 

 spermatophores are attached. In the nearly related Sepiola (also according 

 to researches by v. Maerenthal not yet published), there is a pouch-like 

 depression of the integument lying laterally to the mouth of the oviduct 

 for the reception of the spermatophores ; this has been hitherto erroneously 

 regarded as a terminal portion of the oviduct itself. 



In the other Decapoda, copulation takes place in an exceedingly peculiar 

 way, the spermatophores not being brought into the mantle-cavity, but 

 attached near the mouth ou the outer integument of the lip (buccal membrane) 

 ■of the female. Glandular invaginations of the integument, in which the 

 spermatozoa that escape from the spermatophores are stored, are found in 

 this position iu Sepia and Loligo (Vialleton), in Sepioteiithis and no doubt 

 also in the other genera (v. Maerenthal). 



In this last case, it is evident that fertilisation takes place only when the eggs 

 :are expelled through the funnel and are retained for a time near the mouth by 

 the arms. The future leathery egg-capsule (of Sepia) is either still soft at 

 this time and penetrable by the spermatozoa (?) or only forms after these 

 have penetrated the egg (through the micropyle of the chorion), the still fluid 

 glandular secretion being subsequently poured over the eggs by the funnel. 

 This would then also no doubt apply to the gelatinous mass (in Loligo). It 

 is an interesting fact that artificial fertilisation of mature eggs taken from 

 .a female Loligo Pealii was brought about by means of seminal fluid found in 



the spermatophores of the buccal 

 membrane (Watase, No. 50). The 

 -*1 same conditions are found in Rossia. 



m 



eft 



*k 



B 



Fig. 105. — The upper pole of the egg of 

 *"? Arf/onauta argo in optical section. 

 ."'.1, before fertilisation; B, shortly 



after fertilisation (after Ussow). ch, 

 £[ chorion; d, yolk; ks, germ-disc; m, 



micropyle ; pi, peripheral protoplasm ; 



r&,Spolar bodies. 



longitudinal diameter. The food 



The eggs of the Cephalopoda 

 are unusually rich in yolk, and 

 consequently attain a considerable 

 size, a point in which they are 

 essentially distinguished from 

 those of other Molluscs. The 

 eggs of Sepia, for instance, are 

 fully as large as a pea (Sepia 

 officinalis). The eggs of Eledone 

 may be still larger and are ex- 

 ceedingly rich in yolk (p. 237). 

 The eggs of other Cephalopods, 

 such as Loligo and Octopus, are 

 less rich in yolk and therefore 

 distinctly smaller ; those of Argo- 

 nauta are even rather small, 

 measuring, however, 1*3 mm. in 

 ■yolk, which consists of rather fine 



