PLATE VIII. 
Figure 51. — Egg a few minutes after mixture with the male 
fluid magnified 500 diameters. 
Figure 52. — Egg about thirty minutes after fertilization 
magnified 500 diameters. 
Figure 67. — Section of a portion of the visceral mass of a 
male oyster magnified 250 diameters. The surface epithelium 
of the body is shown at the lower end of the figure. Above 
this is a loose, thick layer of wrinkled cells, which have the 
appearance of adipose cells from which all the fat has been 
removed. Above this layer is a large duct, lined with epithe- 
lial cells, and filled with ripe spermatozoa, which have been 
poured into it from two follicles which communicate with it 
on each side. Above this are sections of a number of the fol- 
licles of the testis, in three of which the contents are figured 
