634 LECTURE XXIV. 



glandular character. In the Loligo sagittata the oviducts commence 

 about one-third of the length of the ovary from its anterior end ; and 

 after a short course are disposed in sixteen close, transverse folds, 

 after which they are continued straight to their terminal glandular 

 division. 



With respect to the act of impregnation in the Cephalopods, Ari- 

 stotle, whose knowledge both zoological and zootomical of this class 

 was great, gives two accounts.* In the fifth book of the " Historia 

 Animalium," he states that the Octopus, Sepia and Loligo copulate 

 in the same manner ; the male and female having their heads turned 

 towards each other, and their cephalic arms being so co-adapted as 

 to adhere by the mutual apposition of their suckers. In this act the 

 Poulps ( Octopus) are said to seek the bottom, while the Cuttles and 

 Calamaries swim near the surface, the individual of one sex moving 

 forwards and the other backwards. It would seem, also, that the 

 modified arm of the male in certain Octopods had not escaped 

 notice, for he adds (oh. v. 1.), " Aiunt nonnulli raarem habere non 

 nihil simile genitali in uno ex brachiis, quod duo maxima acetabula 

 continent : id protendi quasi nervosum usque in medium brachium 

 atque totum in infundibulum faeminae inseri." 



From the position of the vulva or vulvae at or near the base of the 

 funnel, and from the inclination of the penis in the Cuttle to the 

 side corresponding to that where, in the female, the vulva opens, it 

 is most probable that the sexes do combine as above described ; but 

 actual intromission by the vulva seems physically impossible in the 

 Cephalopods. The males may, and probably do, introduce the sper- 

 matophores into the pallial cavity of the female : they have, in fact, 

 been seen attached to the internal surface of this cavity, near the 

 vulva. The male Argonaut leaves the modified spermatophorous 

 arm attached by its suckers to the interior of the funnel or branchial 

 chamber, whence arose the natural mistake as to its being a parasitic 

 worm. The spermatozoa, expelled from the spermatophora while in 

 the branchial chamber, may be conveyed either by the oviduct, or more 

 directly by the aquiferous canals, to the ovarium : and it is certain 

 that impregnation takes place before the ovum has passed into the 

 oviduct and has acquired its nidamental covering. 



The ovarian ova consist of a deep yellow or rose-coloured vitellus, 

 enclosed in a delicate vitelline membrane, which is folded longitudi- 

 nally in the Octopods, and both lengthwise and transversely in the 

 Decapods, the folds penetrating the vitellus, and giving the ova a 

 reticulate exterior. After dehiscence, and when received in tlie 



* CCCLXXVII. lib. iv. and v. 



