BULLETIN OF THE UNITED STATKS FISH COMMISSION. 185 



cause of tlio acquired green oolor of the clam is the same as that of the 

 oyster; that, as in that animal, it is diffuse; is absorbed from the vege- 

 table food consumed by the animal; th;it it is allied to, if not the same 

 as, phycocyauiu; that it is harmless, as has been experimentally demon- 

 strated in the case of the oyster. There is also no reason why green 

 clams should not be as freely consumed as food as green fleshed oysters, 

 which are valued all the more by the epicures of Paris aud Loudon 

 because they arc so discolored, in the belief that such a change of color 

 improves their flavor. 



Washington, January 8, IS85. 



EXPLANATION OF THE FIGURE. 



Side view of the soft parts of the common clam or maimauoso (Mya arenaria) in the 

 position in which it is found in life, with the left valve and mantlo of the left side 

 removed and the loft half of the siphon cut away, so as to expose its iucurrent and 

 excurrent canals. 



a, anterior, a', posterior adductor muscles; b, body mass; cl, cloacal cavity, contin- 

 uous posteriorly with the suprabrauchial chamber: e, wrinkled horny epidermis of 

 siphon; /, foot; g, gills; h, heart ; m, cut edge of the border of the mantle where it is 

 continuous with that of the left side; o, mouth; p p, palps or lips; p o, pedal open- 

 ing in the mantle, through which the foot is extended; r, rectum; 8, iucurrent si- 

 phonal canal ; «', excurrent siphonal canal (the arrows indicate the direction of the cur- 

 rent flowing in and out of the mantle chambers of the animal) ; «,umbo uext the hiuge 

 of theright valve; invent or anus, which opens iato the cloaca. 



43.— THE niCRATIOIV OF SALMON (SAlLiTIO SALAB L.) IIV THE BAL- 

 TIC* 



By JUDGE FIEDLER. . 



As most people know, the salmon-fishery in Denmark is limited in 

 territory; only at and below Boruholm and Christiausoe has there been 

 carried on from time immemorial quite a considerable honk fishery for 

 great salmon. The salmon-weirs in Gudenaa and Skjernaa, at Kolding, 

 Veile, and many places, all have greater importance for the capture of 

 sea-trout (Salmo trutla) than for the salmon itsell (Salmosalar), for which 

 the streams of our little country are loo small and shallow to furnish the 

 desired spawning-grounds. It is only on the island of Bornholm that they 

 are found in a little rivulet and a few larger brooks, which might furnish 

 a refuge for the sea- trout, but are not suitable as spawning-places for the 

 salmon, and there is no information that the salmon ever came into them 

 for the purpose of spawning. The salmon which are caught off Born- 



* Comments in Nordink Aarsfkrift for Fiskeri, 1884, upon " Laxens (Salmo salar L.) 

 Vandringar i Ostersjiin," by Professor Andreas Johau Malmgren, iu Noruk FhkeritU 

 dende,Pnr\ II, April, 1885; pp. 210-215*. Translated from tbo Danish by Tarleton 

 H. Bean, M. D. For Professor Malmgren's article, see Bull. U. S. F. C, 1884, pp. 

 322-328.— EDITOR. 



