Mr. C. Spence Bate's Notes on Crustacea. Ill 



fluence of the male, but through the agency of spermatozoa left 

 within the cul-de-sac since the last or annual intercourse. 



For days previously the male may be seen running about and 

 biding himself under stones, holding the female by one or more 

 of his legs, the carapace being pressed against the sternum of the 

 male; in this relative position they continue until the female 

 throws off her calcareous clothing, when connexion immediately 

 follows and continues for a day or two, perhaps until the shell 

 again hardens. 



IV. It is stated by Couch, in his ' Cornish Fauna,' that when 

 the ova are matured the female detaches them by means of her 

 feet and buries them in the sand, the friction of which frees the 

 larva from the egg. This may be true as far as regards the Bra- 

 chyura, but the manner in which I have observed the larva freed 

 from the ova in Pagurus Bernhardus, is by their being passed 

 through the branchial chamber. 



During the attachment of the ova to the false feet of the pa- 

 rent, which in the female PaguridcB are bifid, but simple in the 

 male, they are continually waved forwards and back in the sur- 

 rounding medium : this movement supersedes the want of those 

 flabellseform appendages which are attached to the false feet of 

 the female Brachyura, and which fulfill, I presume, a similar office 

 towards the ova as the true flabella? perform for the gills, which 

 is to excite a current over their surfaces. 



When the ova are matured they are drawn off from their at- 

 tachment, most probably by the assistance of the fifth or rudi- 

 mentary pair of feet (which are very useful to the creature for 

 many purposes), after which they are driven into the branchial 

 chamber by the current which passes in to aerate the blood, while, 

 in its passage through, the larva is freed from the membranous 

 shell of the ova, and set at liberty. 



A few which I examined that fell directly to the bottom of the 

 shell which the crab inhabited, without passing through the gill- 

 chamber, were not so freed from the egg, nor could they swim 

 about as the others did. 



EXPLANATION OF PLATE VIL 



Figs. 1, 2. False feet of male, Carcimis mcBnas, shown anteriorly and pos- 

 teriorly : A. The external portion of the vas deferens as it is seen 

 passing from the first joint of the fifth pair of legs to the false feet. 



Fig. 3. First pair of false feet in Cancer pagurus. 



Fig. 4. Second pair of ditto ditto. 



Fig. 5. Lateral view of first and second pair of ditto, showing theii" relative 

 position : A. Process to assist in erection. 



Fig. 6. Cells containing spermatozoa of Carcinus rncenas. 



Fig. 7- Ditto from Cancer pagurus. 



Fig. 8. Ditto fi-om Pagurus Bernhardus. 



Fig. 9. Ditto fi-om Galathea strigosa. 



