54 8 



AMPHIBIA. 



it bears on the outer side near the cloaca a dilated glandular 

 mass or "seminal vesicle." In the males, rudiments of the 

 Miillerian ducts are sometimes seen. 



The paired ovaries when mature are large plaited organs, 

 bearing numerous follicles or sacs containing the pigmented 

 ova. The spawn laid by a single frog may consist of several 

 thousand eggs. The ripe ova are liberated into the body 



Fig. 234.— Urogenital system of Fig. 235. —Urogenital system of 

 male frog.— After Ecker. female frog.— After Ecker. 



f.b., Fatty bodies; v.c, vena cava; ovd., Opening of oviduct ; ov ovary 

 T., test.s; K., kidney ;w.d Wol- f.b., fatty body; K., kidney; Ut.\ 

 ffian duct ; cl., cloaca ; Bl., bladder. uterus ; Ur., opening of ureters into 



cloaca (cl.), in front of the openings 

 of the oviducts. 



cavity, and moved anteriorly towards the heart, near which 

 the oviducts open. The movement of the ova is mainly 

 due to the action of peritoneal ciliated cells, which converge 

 towards the mouths of the oviducts, but partly to muscular 

 contraction, including the beating of the heart. The 

 oviducts are long convoluted tubes, anteriorly thin-walled 

 and straight, then glandular and coiled, terminally thin- 



