38 
BULLETIN OP 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 vulvse 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 sperinatophores it has seemed possible “ that 
the sort of stopper in question left in the vulva may have been 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 he 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 lias 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.” 
Milne 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 tvere laid, as occurs in the tailless Batracliians; he 
