r. c. 



v.c. 



Microns 



Figure 81. — Cross section of a small artery of the mantle, bl.c. — blood cells; e.lf. — elastic fibrils; end. — endothelium; 

 f.c. — fusiform cells; r.c. — round cells; v.c. — vesicular ceils. Kahle, hemato.xylin-eosin. 







Microns 



30 



Figure 82. — Two vesicular cells from the mantel of an adult C. virginica. Left — the cell contains f^lycogen stained 

 with Best's carmine; fat globules were dissolved in processing. Right — similar cell after fixation with Bouin :{; note 

 complete absence of glycogen and fat, both dissolved during fixation and dehydration. 



dissection. Such nhuiulaiice of reserve material 

 led one of the earlier iinestigators (Creighton, 

 189G, 1(S99) to conclude that its storage in tlie 

 connective tissue of laniellibranclis is a special 

 adaptation compaiai)le to the storage of fat in 

 the connectixe tissues of vertebrates. 



The (|uantity of glycogen stored in connectixe 

 tissue gTaduallj' decreases as the gonads of the 



oyster increase in hulk. This was first reported 

 for (). ((htlis by Pekelharing (1901) and confirmed 

 by the more recent investigations of Bargeton 

 (1942). Evidence presented in the latter work 

 strongly suggests that tlie growing sex cells utilize 

 tlie glycogen stored in the vesicular cells sur- 

 rounding the gonad tulndes, but cytological details 

 of this process are still unknown and tlie ])roblein 



82 



FISH AND WILDLIFE SERVICE 



