934 REPORT OF COMMISSIONER OF FISH AND FISHERIES. [4] 
among acephalous mollusks—of its being entirely independent of the 
digestive system; although placed in the ventral region, it has no con- 
nection with the intestines. The gills, or breathing organs, four in num- 
ber, are in the shape of large lamin nearly equal in size and with trans- 
verse striations; they are arranged symmetrically, two on each side of 
the body. When viewed from behind, four rows of large and perfectly 
regular quadrangular openings are seen. These openings pass through 
the gills in the form of canals, in which the fecundated eggs accumulate 
at the spawning time, in order to undergo a sort of incubation. 
The organs of reproduction consist of an ovary placed along the 
sides and upper portion of the head end of the body, and which 
finally, as it becomes developed, almost entirely covers the abdominal 
mass. The oyster is hermaphrodite, that is to say, combines the two 
sexes in one and the same individual. The organ of generation, which 
is scarcely visible during the winter, is nevertheless distinguishable in 
the form of a milky spot covering a portion of the liver. In the spring 
almost the entire upper portion of the creature has assumed a whitish 
color; the zoosperms appear; and their presence effects fecundation. The 
oyster yields from 50,000 to 60,000 eggs, more or less.* They are 
spherical and can only be seen by the aid of a microscope The embryo 
develops rapidly, is soon provided with vibrating cilia at the anterior end 
and swims round and round; finally it settles upon some solid object, 
perhaps on an oyster shell, to which it attaches itself and begins to 
grow. At this time the body of the oyster, being extremely soft and its 
shell very thin, the valves take the impress of the body upon which it 
happens to fall and fix itself, and preserves the shape so assumed ever 
after. 
B.—A NEW MIXTURE TO BE PLACED UPON COLLECTORS.— 
PRESERVATIVE BOXES. 
Without wishing to repeat whatis already known or to treat of asub- 
ject which has been handled by others, I shall in a few lines render 
homage to those intelligent and laborous workers who by the rational 
application of new methods have greatly contributed to the develop- 
ment of oyster culture. I propose to speak of the new collector or 
apparatus for collecting the “fry,” as soon asit is set free by the parent 
oysters and preserving it from destruction. 
It is but a few years since the only methods in use were the following: 
In Lake Fusaro, in the province of Naples, where the oldest artificial 
oyster banks were established, and on our coasts of Brittany, Cancale, 
Saint-Brieuc and Arcachon, the oysterculturists did nothing to collect 
the spat beyond placing bundles of whitewashed fagots in the water, 
anchoring them by means of stones. The spat lodged upon these fagots, 
after which the breeder had only to take them from the water, when as 
[*Now known to yield a much greater number.—ED. ] 
