38 BULLETIN OF THE UNITED STATES FISH COMMISSION. 



in the Brachyura. In the Brachyura he found that a true copulation took place: "The 

 wands of the male penetrate into the copulatory pouches situated below the vulvae of 

 the female, and deposit there the semen, which is so held and preserved in that part 

 that it may be turned over the eggs as fast as they pass out." On the coasts of Brittany 

 Milne Edwards found a female Cancer pagurus, which was fertilized, "and in which the 

 extremities of the wands of the male were broken off after copulation, as happens in 

 many insects; these organs remained inclosed in the copulatory pouches." As 

 Brocchi (25) observes, Milne Edwards seems to have foreseen the presence of sperma- 

 tophores, for in a subsequent work (59) he says, in reference to this observation, that 

 since his attention has been directed to spermatophores it has seemed possible "that 

 the sort of stopper in question left in the vulva may have beeu a body of that nature 

 rather than a fragment of the penis." 



In regard to the reproduction of • the Macrura, where there is no internal seminal 

 receptacle, the fecundation of the eggs, says Milne Edwards (58), is less easily under- 

 stood : 



It is generally admitted that in all these animals there is a true copulation, in consequence of 

 which the seminal fluid is introduced into the interior of the generative organs of the female. If it 

 were not so, it would be difficult to understand how the eggs, which fill the entire ovary, the first of 

 which are laid a long time before the last are developed, come in contact with this fluid, as a necessary 

 condition of their fertilization. But there is not, so far as I know, any direct observation which proves 

 the existence of such a copulation, and the absence of a copulatory pouch leads us to suppose that in 

 these animals the eggs are fertilized as in the cricket, or very shortly after they have left the body of 

 the mother. After being received into the cavity of the ovary, the egg is directed little by little 

 toward the external orifice of one of the oviducts, the walls of which secrete in spring a rather thick, 

 albuminous liquid, which, hardening after the eggs are laid, forms a second external envelope. 



This error of attributing the viscous secretion to the oviducts has been repeated 

 by subsequent writers, notwithstanding the fact that it was corrected by Milne 

 Edwards (60) in a subsequent work. He says in a note following a recapitulation of 

 the observations of Lereboullet, that the glue by which the eggs are attached does not 

 come from the walls of the oviduct, but is secreted by subcutaneous glands situated on 

 the under side of the abdomen, between the bases of the appendages. A membranous 

 penis is said to be formed by the subdermal portion of the seminal tube, which is here 

 enlarged and has thickened walls. This dilated portion of the canal, the " vecteur" of 

 the sperm, ''is capable of evaginating and passing outside beyond the genital opening, 

 to the borders of which it is inserted. It thus forms a tubular appendix, having the 

 function of a penis." 



Milue Edwards was undoubtedly mistaken in supposing that the large glandular 

 segment of the vas deferens of the Macrura was evaginated in copulation. This, as 

 Grobben remarked, would be mechanically impossible (83). 



Duvernoy (57) in 1850 again raised the question whether fertilization in Decapod 

 Crustacea took place at the moment the eggs were laid, and comes to the conclusion 

 that in Macrura and some Brachyura, where there is no seminal reservoir, fecundation 

 takes place without a true copulation. He says : 



The way in which the oviducts are stuffed like sausages with large numbers of eggs arranged in 

 line, when they have reached maturity, would not admit of an internal fertilization, except for those 

 eggs which were brought near the orifice, unless there was a copulatory pouch or a seminal reservoir? 

 before the mouth of which they must successively pass at the time of egg-extrusion, in order to be 

 fertilized, as is the case with insects. 



He supposed that in all cases where internal fecundation was impossible, the eggs 

 were fertilized at the moment they were laid, as occurs in the tailless Batrachians; he 



