THE ZooLocist—June, 1876. 4937 
are raised relative to the reproduction, or “spatting,” of this most 
palatable mollusk. Among the most prominent of these is that 
relating to the obscure and much disputed one as to the sexual 
distinctions of the oyster—or, indeed, whether any such do exist. 
The majority of witnesses, including Mr. Frank Buckland, hold to 
the opinion that this bivalve is essentially hermaphrodite; that is, 
that both the male and female elements are combined in each and 
every individual, and that the eggs produced are self-fecundated. 
This opinion receives support from the circumstance first noticed 
by Leuwenhoeck so far back as the year 1697, viz., that the living 
embryos, or spat, are found fully developed within the mantle-folds 
of the parent—a fact which, associated with the fixed or stationary 
habits of the animal, at first sight considerably favours the her- 
maphrodite theory. This same opinion is universally supported in 
popular treatises on the oyster. During the course of the inquiry 
before the Parliamentary Committee, however, one witness, Mr. 
Austin, an oyster merchant from Canterbury, produced some im- 
portant evidence in a contrary direction. This witness entirely 
disagreed with the hermaphrodite theory, and considered the sexes 
to be distinct, also remarking that the phenomena known to oyster 
cultivators as the “white” and “black” sickness among oysters 
was, in his opinion, characteristic in the first instance of the male, 
and in the last of the female representative of the species. The 
reasons given by Mr. Austin for this statement were through his 
having ascertained, with the aid of the microscope, that in the case 
of the black sickness the little oysters were fully formed, while 
with the white no such formation was discernible. Mr. Austin 
had further observed that the black sickness came later than the 
white—a circumstance to which he thought the present scarcity of 
oysters was due. To insure a successful “spat,” he considered 
that the white and black sickness should occur together. 
While not endorsing the opinion of Mr. Austin expressed in the 
- Jast two sentences, there are strong grounds for believing that his 
deductions concerning the sexual individuality of the oyster are 
correct, as also that the distinctions between the two sexes are 
associated with the phenomena he observed. The common fresh- 
water mussel (Anodonta cyqnea) is, in fact, a case in point, where, 
under almost parallel circumstances, it has been satisfactorily 
ascertained that the different sexes are in separate individuals. 
In this species the ova are lodged, and the embryos developed and 
