78 DESCRIPTIONS OF PREPARATIONS. 



The kidneys are concealed by the fat bodies and genitalia. The former are 

 golden yellow in the fresh state, vascular, and of unknown use. The testes vary in 

 size according to the time of the year. The vasa efferentia run towards the inner 

 border of the kidney : the majority fall into a longitudinal vessel close to that 

 border, while a few may end blindly. From this vessel transverse canals, dilated 

 at their origin, pass outwards, receive tubuli uriniferi, anastomose, and fall into the 

 ureter or Wolffian duct, which runs on the outer margin of the kidney. In the 

 Toads the efferent vessels unite with functional Malpighian corpuscles, represented 

 perhaps by the dilatations (supra) in the Frog. A solid remnant of Miiller's duct 

 may be found running forwards on the outer margin of the kidney. It ends 

 blindly. In the Toads this remnant is large, hollow, and uniting with its fellow, 

 opens on the dorsal wall of the cloaca. Each ovary is divided by internal septa 

 into fifteen sacs : the outer surface is lobed. The two oviducts commence by 

 slit-like openings close to the roots of the lungs. At first narrow and straight they 

 become convoluted and glandular, and finally, near their termination, thin-walled 

 and dilated. Narrowing again, they open on papillae situated anteriorly to the 

 openings of the ureters on the dorsal wall of the cloaca. The kidneys are semi- 

 lunar glands covered by peritoneum only on their ventral faces. Whitish spots, 

 especially numerous near the efferent veins, mark the position of the nephro-stomata 

 or ciliated funnel-shaped apertures which open into the abdominal cavity and are 

 connected by ciliated tubes with the tubuli uriniferi in the Tadpole (as in Urodeles 

 throughout life) ; but in the adult, according to Nussbaum, with the reni-portal 

 capillaries. The ureter (Wolffian duct) begins at the anterior end of the kidney, 

 runs along the outer margin, and, in the male, is dilated and glandular just where 

 it quits the kidney, forming the receptaculum seminis. Both ureters open on the 

 dorsal wall of the cloaca separately. The supra-renal capsules are yellow when 

 fresh and lie in the median line on the ventral face of the kidneys. 



Amphibia, Hoffmann, Bronn's Klass. und Ordnungen des Thierreichs, vi. Abth. 

 2. 1873-1878; Huxley, Encyclopaedia Brit. (ed. ix.), i. Anura Batrachia d. Deut- 

 schen Fauna, Leydig, Bonn, 1877. 



Rana temporaria. Bell, British Reptiles, London, 1839, p. 84. 



The Frog. Ecker and Wiedersheim, Anatomic des Frosches, Brunswick, 

 3 parts, 1864, 1 88 1, 1882 (with references to literature), in process of translation. 

 A. M. Marshall, Owen's College Course of Elementary Biology i. (ed. 2), 1885. 

 Figures. Atlas of Practical Elementary Biology, Howes, 1885. 



Integument. Leydig, Allgemeine Bedeckungen, &c. A. M. A. xii. 1876. Chro- 

 matoblasts and change of colour, Lister, Ph. Tr. 1858, p. 627. Connection of chro- 

 matoblasts with nerves, Ehrmann, SB. Akad. Wien. Ixxxiv. Abth. 3. 1882. Nerve- 

 endings. Merkel, Endigungen der sensibeln Nerven in der Haut, Rostock, 1880. 

 Cf. On the Epidermis of Salamander, Pfitzner, M. J. vi. 1880. The periodical moult 

 of cuticle, Knauer, Z. A. ii. 1879. 



Digestive tract. Teeth. Tomes, Ph. Tr. 1875; Hertwig A. M. A. xi. (Suppl.), 

 1874. Intermaxillary gland, Wiedersheim, Z. W. Z. xxvii. 1876. Tongue, organs 

 of Taste. Engelmann, Strieker's Histology (Sydenham Soc.), iii. 1873, p. 14. Cf. 

 Z. W. Z. xviii. 1867-69. Glands of Stomach. Partsch, A. M. A. xiv. 1877. Cf. 

 Swiecicki, Arch. f. Physiol. (Pfliiger's), xiii. 1876. 



Lungs. Schulze, Strieker's Histology (Sydenham Soc.), ii. 1872, p. 72. 



