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



so-called false feet continuing through and terminating at the 

 apex in an oval slit. I can only account for the confident man- 

 ner of Prof. Milne-Edwards's expression in hoth places to which 

 reference has already been made, that direct observation has 

 shown that these styliform processes are not used except to di- 

 rect the true organs towards the vulvae, or perhaps to excite the 

 female: "Ces appendices paraissent devoir servir k diriger les 

 verges vers les vulves, et peut-etre aussi a exciter ces derniers 

 organes " (Histoire des Crustaces, vol. i. p. 169), by presuming 

 that the slight membranous tube must have been ruptured, it 

 being very fragile and delicate in its external passage. 



I can only add, that I have preparations from which the ac- 

 companying illustrations are taken, in which they are distinctly 

 seen as they may be by any who will but observe the living ani- 

 mal, being careful in turning back the abdomen that the canal 

 be not broken. 



Internally the tube unites with the testicle, which is a long 

 white cord inflected repeatedly upon itself, and lies beneath the 

 carapace on either side of the stomach. This is different from 

 the Paguridce, among which they extend into the abdomen. 



II. Throughout the Brachyura the spermatozoa seem to re- 

 semble each other, and the only appreciable difference that I can 

 make out is to be found in the cells in which they are produced, 

 which vary slightly in shape, being generally round or oval in 

 Cancer pagurus, more irregular in Carcinus. 



But in the Anamoura [Pagurus Bernhardus) the cells differ, 

 being long and narrow with a sharp and slightly turned point at 

 one extremity and narrow and square at the other. But the 

 spermatozoa themselves do not offer any difference from that of 

 the preceding. 



On Fertilization in the Female. 



III. I have been induced to believe that crabs, like certain kinds 

 of insects, have more than one brood to a single inoculation by 

 the male ; the data upon which I have formed this opinion is, that 

 early in this spring (May) I took a female which had but recently 

 set the larva at liberty, the hair-like connection, together with 

 the shell of the ova, still remaining attached to the false feet. 

 Upon afterwards dissecting this creature and examining the in- 

 ternal organs, I found them full of ova in a very early state of 

 development. 



Coupling this with what I believe to be a fact, that the male 

 can only impregnate the female immediately after the shedding 

 of the exuviae, and that this in adult crabs only takes place once 

 in the year, I must conclude that the ova within the gravid 

 uterus could only have been fertilized, not by the immediate in- 



