CH. VI] THE FRESH- WATER MUSSEL 177 



glutinous mass in which the crystalline style is slowly 

 differentiated, the process being complete by October. 

 The remaining jelly, apparently superfluous food material, 

 passes into the first section of the intestine and by 

 November the stomach is empty of it. In the intestine 

 the- jelly becomes compacted to form the crystalline style 

 which is slowly consumed during the winter months. 

 Haseloff 1 maintains that the style is a reserve of food, 

 disappearing during periods of fast and reappearing when 

 food is taken. Mitra 2 , who has recently investigated 

 the matter, adopts an entirely different explanation; in 

 his opinion the style is a digestive ferment whose function 

 is to convert starch to sugar; he finds that much food 

 surrounds and is embedded in that end of the style which 

 projects into the stomach and that the style itself is 

 formed and vanishes again about once a day, being 

 present whenever digestion is going on; it is a colloid 

 proteid of the globulin class, is soluble in water and is 

 probably excreted by the "liver" as a viscous fluid. 



I am unable to confirm Mitra's results; specimens that 

 had been fasting for two days (in October) I found to contain 

 well developed styles, these after removal from the body 

 remaining undissolved in cold water for three days and 

 were then removed; when fresh styles were placed in 

 dilute solutions of starch for several days I was unable 

 to detect the presence of sugar; the proteid reactions of 

 the style were however very well marked and there were 

 indications of the presence of peptone. It is evident that 



1 Biol. Centralbl. vn. and Kiel. Inaug. Diss. Ostarode, 1888. 



2 Q.J.M.S. XLIV. 1901, with literature references. 



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