PLATE 41. 



Fig. 46. Gyrocotyle fimbriata. Same specimen as fig. 42. Ventral. 

 Showing vagina and vaginal opening, vesicula seminalis, penis-papilla 

 and ejaculatory duct. X 100. 



Fig. 47. Egg from fifth coil of uterus. Showing single ovum sur- 

 rounded by numerous yolk-cells. Delafield's haematoxylin. X 1000. 



Fig. 48. Same, tenth coil of uterus. Showing division of ovum and 

 disintegration of yolk cells. Note disappearance of nuclei of yolk cells. 

 X 1000. 



Fig. 49. Yolk cells in vitellarian follicle. Note reduction of cyto- 

 plasm and formation of yolk-platelets. X 1850. 



Fig. 50. Spermatozoa from receptaculum seminis, showing head, tail 

 and acrosome. X 1850. 



Fig. 51. Ovum in afferent oviduct; note shadow of yolk nucleolus. 

 X 1500. 



Figs. 52, 53, 54. Follicle of ovary. Showing syncytial ova and various 

 stages in the formation and extrusion of the yolk-nucleolus. X 1500. 



cyt. r. cytoplasmic rim. 



ejac. duct ejaculatory duct. 



in. long. inner longitudinal muscle. 



ov. ovum. 



pen. pap. penis papilla. 



sptz. spermatozoa. 



ut. uterus. 



vag. vagina. 



vag. op. vaginal opening. 



vas def. vas deferens. 



yk. c. yolk cell. 



yk. gr. yolk platelets. 



yk. nucleo. yolk nucleolus. 



[454] 



