On the Economical Uses of some species of Testacea. 245 



condition, but by the end of August ihey have again recovered, are 

 fat and in season. The sexes are distinguished by the fishermen, 

 by the color of the fringe, that of the male being black, or dark col- 

 ored, that of the female white. Sand is prejudicial to them, a mix- 

 ture of fresh water advantageous. The shell, according to Mr. 

 Hatchett, is formed of carbonate of lime and a great proportion of 

 animal gluten, but more intimately mixed, and not lying in regular 

 layers, as in the perlaceous shells.* The oyster frequently contains 

 shining intestinal worms, or animalcules, which may be seen by 

 opening the shell in the dark. A most destructive animal in an oys- 

 ter bed is the sea-star, {Asterias glacialis, Linn.) which clasps its 

 rays round the shell and perseveres till it has sucked out the inhabit- 

 ant. Another enemy is said to be the muscle, [Mytilus edulis, 

 Linn.) 



Fishery. — In both England and France the season for fishing for 

 the oyster is restricted by law. In the former country the time al- 

 lowed for collecting the spawn from the sea is May, when the dredg- 

 ers may take all they can procure, but after that month Ihey are 

 liable to be convicted of felony if they disturb it, and are only allowed 

 to take such oysters as are the size of half a dollar. The spawn, 

 or spat, as it is technically called, is dredged up, and if not too small, 

 they separate it from the shells and stones to which it is adhering, 

 and these they are obliged again to throw into the water to prevent 

 the beds being destroyed. The spat is thrown into creeks or into 

 shallow water on the shores, to increase in size and fatten, and in 

 such situations is considered private property. At Preston Pans the 

 oysters are not bedded, but are entirely procured from the sea, and 



* Professor Rogers doubts the accnracv of this analysis, as regards the quantity 

 of animal matter contained in this shell, and he supposes that there only exists a 

 very minute portion of gluten. In this opinion he states that he is supported by 

 the experiments of Bucholtz and Brandes, and those he himself made on the Os- 

 trca Virginica. What the shells were which were used by the former gentleman, 

 we are not informed ; but with all deference we would suggest that he himself 

 seems to have forgotten that ttie American and British shells are quite distinct 

 species, from which most probably arises the difference he has discovered, and 

 which instead of proving Mr. Hatchett's experiments to be in the main incorrect, 

 only tends to prove that the species are perfectly distinct, and not mere varieties. 

 The quantity of gluten contained in the Ostrea edulis, is well known to even the 

 most superficial observer, where the shell is common, and maybe found in the 

 large and thick specimens, or on the decaying of the shell, between the inner and 

 outer laminse, frequently in great quantities. It is of a dirty yellow color, and 

 thick and clammy in its consistency. See Silliman's Am. Jour., Vol. xxvi, p. 361. 



