1002 REPORT OF COMMISSIONER OF FISH AND FISHERIES. © [2] 
VII. Works relating to the oyster-fisheries and the cultivation of 
the oyster on the coasts of Denmark, Sweden, and Norway. 
VIII. Works relating to the attempts to establish oyster-beds on the 
coasts of the Baltic. 
IX. Works relating to the oyster-fisheries and the cultivation of 
the oyster on the coasts of the Mediterranean and Adriatic. 
X. Works relating to the oyster-fisheries and the cultivation of 
the oyster on the east coast of North America. 
XI. Works relating to the oyster-fisheries and the cultivation of 
the oyster on the coast of China. 
Alphabetical index. 
The investigations relative to the ANATOMY OF THE OYSTER were in 
charge of Messrs. Hock, Vosmaer and Waalewijn. 
Dr. Hoek writes that, as far as the generative organs are concerned, 
the more important questions are those relating to physiology, at least 
in viewing the matter from the point of view of an oyster cultivator. 
These questions—to mention some of them—are as follows: At what 
age does the oyster begin to propagate? What percentage of the oysters on 
a bed take part in the propagating process? Does the propagating oyster 
exercise the functions of one sex or of both sexes? Does one and the same 
oyster propagate once or more than once a year? &c. All former investi- 
gators, who have occupied themselves with this subject, have attempted 
to answer these and other similar questions. The reason why they did 
not succeed—for even the investigations made by the most prominent 
among thein (Davaine, Lacaze-Duthiers, Mobius, &e.), have not led to 
any certain results, but only to more or less doubtful suppositions—must 
be found in the circumstance, that an attempt was made to answer these 
questions, without any satisfactory knowledge of the anatomical (both 
macroscopic and microscopic) construction of the oyster. 
What is the construction of the generative organs? Where are they 
located? How are the generative products emitted? These three ques- 
tions seem so simple that it is difficult to imagine that they could not 
be satisfactorily answered by the aid of the experience of former inves- 
tigators. The oyster is not such a rare shell-fish, nor can it be classed 
among those animals which, on account of their small size, are difficult 
to examine. The fact that its anatomy is particularly little known is 
doubtless owing to the circumstance that the oyster—more than other 
mollusks—presents great difficulties to the use of the dissecting needle, 
scalpel, and magnifying glass, to such a degree as to make such experi- 
ments appear futile and bring them to an abrupt close. Our more mod- 
ern methods of investigation cannot yet be said to be entirely suited to 
the nature of the oyster; it will nevertheless be to these methods that 
we will have to look for a speedy and deeper insight into the construc- 
tion of the generative organs. 
These methods consist principally in hardening the oyster and in ob- 
