Bull. U. S. B. F., 1921-22. (Doc. 922.) 



BijG--MM 



WG--- 



PdA CM 



FiG. 142.— Photomicrograph of main byssus gland in cross section. X 8. Fixed in Gilson fluid and stained with 



Delafield hematoxylin. 

 Fig. 143. — Sagittal section through foot. X 6 approximately. 

 Fig. 144. — Cross section of foot taken just posterior to sucker. 

 Fig. 145. — Cross section of foot in the mid region. X 7 approximately. 



Abbreviations.— BS, blood sinus; BV , blood vessels; ByG, glandular lamellae of byssus gland; ByP, byssus 

 pit; CM, circular muscles; LM, longitudinal muscles; PdA, pedal artery; PdV, pedal vein; PrG. purple gland; 

 S, sucker; VGr, ventral groove; WG a white gland. 



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