638 GIBSON ON ANATOMY AND PHYSIOLOGY OF PATELLA VULGATA. 



Fig. 66. Cartilages of odontophore, horizontal section, dorsal view, ax., anterior cartilage ; p.c, 

 posterior cartilage; I.e., lateral cartilage; v.tr., deep ventral transverse muscle; b., con- 

 nective tissue and perichondrium. 



Fig. 67. Stomach wall. The section is taken transversely through a part where the adjacent walls of 

 the two divisions of the stomach touch. 



Fig. 68. Vertical section through the visceral dome, a, pericardium; b, in the stomach; ex, sections 

 of intestine ; d, in the right nephridium ; e, section of rectum ; /, left nephridium ; g, 

 glandular stomach, "crop"; h, genital organ; k, liver; /, foot. 



Fig. 69. Transverse section of intestine near rectum. 



Fig. 70. Cells of a follicle in glandular stomach. 



Fig. 7 1. Glandular stomach and liver, a, follicles ; b, liver sacs ; c, bile duct. 



Fig. 72. Cells of the intestine isolated and more highly magnified. 



Fig. 73. One of papilla? of rectal papilla wall. 



Fig. 74. Transverse section of rectal papilla. 



Fig. 75. Membrane covering the genital organ. 



Fig. 76. Ova, in different stages of development. 



Fig. 77. Development of spermatozoa. 



Figs. 78 and 79. Two stages in the development of a tuft of spermatozoa. 



Fig. 80. ' Spermatozoa isolated. 



