PARTICULAR ORGANS OF SECRETION. 175 



into that cavity in the Squamigerous, a constantly firm chalk-like 

 and crystalline urinary secretion, but which is on the contrary in the 

 Naked Reptiles in a fluid state. There arises usually from the 

 anterior walls of the cloaca (with however it would appear the ex- 

 ception of the Ophidia) a bladder which is usually small and round- 

 ed in the Sauria, elongated but simple in the Sirens, in the Chelo- 

 nia mostly slit into two round lobules, and frequently, as in the 

 Batrachia, fissured and developed to a very great degree ; this is fill- 

 ed usually with a large quanity of colorless fluid, and has been viewed 

 as an urinary bladder. Its walls are very thin and membranous, 

 traversed by vessels, and the fluid contained therein consists of real 

 urine and uric acid. 



The Renal Capsules are found in all the Squamigera, and may 

 be distinctly demonstrated in all the larger Serpents, Lizards, and 

 Tortoises ; they are mostly of a yellowish color, elongated in form, 

 and are usually situated above the kidneys, either within the folds 

 of the peritoneum, or more freely near to the sexual organs ; inter- 

 nally they rest upon the vena cava, to which they are united by ves- 

 sels. Besides the Ichthyodea, they are wanting also in the Batrachia, 

 but in the Anoura, we meet with large, yellow-colored lobes of fat 

 divided in a digitate manner, and placed upon the anterior extremities 

 of the kidneys, while delicate streaks of granular fat course over the 

 anterior surface of those organs. 



PARTICULAR ORGANS OF SECRETION. 



IN the order Amphibia the tegumentary follicles are occasionally, 

 as in the Toads and Salamanders, developed to a very considerable 

 degree, being in part distributed in small groups over a great extent 

 of the body, and forming, e. g, in Bufo and Salamaridra, a protuber- 

 ant conglomerate mass upon either side the head behind the ears. 

 In the Salamanders and some Tritons they are situated chiefly in 

 rows along the back ; these follicles, as well as the crural glands of 

 the Lizards, have been described in treating of the tegumentary 

 system. Each aperture leads into a pouch, the commencement of 

 which is slit into small blind pockets or coeca. In some Sauria an 

 aperture is constantly found behind the anus, which conducts 

 into a small pouch secreting a substance of a peculiar odor. 

 The analogous follicles in many of the Ophidia, as in the com- 

 mon Snake (Coluber natrix), male as well as female, are very 

 long and distinct. They are situated below the vertebral column 

 near to the penis and behind the anus, upon the verge of which they 



