FISHERIES OF THE UNITED STATES. 4^ 



Figure 51. — Egg a few miuutes after inixtnre with tbe male fluid 

 magnified 500 diameters. 



Figure 5"i. — Egg about thirty minutes after fertilization mag- 

 nified 500 diameters. 



Figure C7. — 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 largo duct, lined with epithelial 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 follicles of the testis, in three of 

 which the contents are figured. 



Figure 53. — Section of a portion of the viscera mass of a female 

 oyster magnified 250 diameters ; «, epithelium of the surface of 

 the body; 1), layer of connective tissue; c, layer of wrinkled cells, 

 which are probably fixt colls, from which all the fat has been re- 

 moved; /, sections of ten ovarian follicles; e, the ovarian eggs.. 



Figures 54-66. — Abnormal or direct form of segmentation. 



OSTEEA LURIDA, Cpr.— West coast oysters. 



32879. Natives. Crescent City, Cal. W. H. Call. 



32809. Natives. Shoalwater Bay, W. T. H. Hemphill. 



32798. Natives. San Diego, Cal. H. Hemphill. 



32798. Eastern oyster (0. virginica). Taken from Newark Bay, N. J., when * 



year old and planted in San Francisco Bay ; showing two years' growth 



in California waters. 



Extra-limital : 



32878. Fossil oyster from marine Tertiary beds near Vicksburg, Miss. Closely 

 resembling the present English oyster. 



32311. Fresh specimen, English oyster (0. ediilis, Linn.). Introduced for com- 

 parison with the American fossil and recent oysters. North Sea. Dr^ 

 Wm. Stimpson. 



MARINE PLANTS. 

 I. ALa^. 



39126. Three portfolios of Algae of North America, prepared by Prof. D. <«. 

 Eaton, Dr. C. L. Anderson, and Dr. W. G. Farlow. 



4f 



