46 



■Renal and rvEPRooucTivE Organs — 



Flu. 7. Male Oeoans from the ventral surface. Tlio riglit testis is turned over to sliow its efferent 

 ducts — 

 Testes ou tlie veutral side of ]iidne3's. 



Vasa eii'erentia (L. afferent vessels), leading to inner side of kidney. 

 Kidneys in tlie dorsal part of abdominal cavity. 



Duct passing from outer side of kidney to open into cloaca — Genito-urinary canal, because 

 it serves as ureter for the kidney and vas deferens for the testis. 

 Fio. 8. Female Organs removed from body — 



Ovary mucli folded and distended with ova. 



Oviduct distinct from ovary, anterior end opening beside gullet, posterior end in cloaca. 

 Ureter .slender and opening into cloaca, posteriorly to oviduct. 

 Openings into cloaca — llectum. 



Urinary bladder, on ventral side of rectum independent of ureter. 

 Oviduct, anterior to opening of ureter. 

 Ureter-. 

 Figs. 9, 10. jMalpighian Cap.sule of Human Kidney — 



Tiilmle witli its rounded dilatation, the Malpighian capside. 



Glomerulus (L. a ball), the tuft of looped capillaries formed by afferent vessel from renal 

 artery, and uniting again to form an efferent vessel (vein), which breaks up into capil- 

 laries on the wall of the tubule. 

 Epithelium of capsule, glomerulus, and tubule. 

 Fig. 11. Malpighian Capsule of Frog's Kidney — 



Epithelium lining tubule, with cilia to expel the urine. 

 Fig. 12. Ovum and iSpermatozoon of Common Feog — 

 Spermatoz(.ion with vibratile tail. 



Tadpole or Larval Frog at different Stages. 



Figs. 13, 14. External Branchi^, three on each side of neck. 



Suckers, dilatations of the integument secreting a sticky substance. 

 Horny jaws. 



Operculum or gill-cover beginning to form. 

 Fig. 15. Operculum grown over gills, leaving only a small opening on left side for some time. 



Hind-limbs appearing at first as tubercles, fore-limbs hidden by operculum. 

 Fig. 1 G. Head of very YOtrNG Tadpole, magnified — 

 Visceral clefts, six on each side of neck. 

 Esternal branchiae, two on each side of ueck (a third pair afterwards developed 



