318 EXTERNAL GENERATIVE ORGANS, BY E. KLEIN. 



Most Amphibia possess erectile tissue, which either surrounds the 

 penis like a sheath, as in Saurians, or is everywhere well developed 

 in the penis and the glans, as in Tortoises and Crocodiles. 



In many Mammals bony plates or rods occur in the penis. Thus, for 

 example, in Cats there is a short osseous lamina at the apex of the 

 glans above the urethra, which posteriorly towards the corona glandis 

 has a small roundish cartilaginous nucleus upon it. The corpus 

 cavernosum glandis extends semi-circularly round the osseous plate 

 and the cartilaginous nucleus. 



In Cats, instead of the corpora cavernosa penis, there is a cylindri- 

 cal body containing fat cells, and enclosed by a dense tunica albuginea, 

 subdivided by a framework of connective-tissue trabeculas. Along 

 the lower side of this body extends a thin layer of large veins which 

 anastomose with one another to form a plexus. 



B. FEMALE ORGANS. 



I. LABIA PUDENDI. In these all the elements of the skin 

 are present. The basis of the labia majora consists of a mesh- 

 work of connective-tissue trabeculse that radiate outwards 

 towards the periphery. In the deeper parts the meshes are 

 looser, representing the subcutaneous tissue, but towards the 

 epidermis they become denser and closer to form the cutis. 



In the looser portions, groups of fat cells, large vessels, and 

 nerves are abundant, together with many large sweat glands 

 and hair follicles. The sebaceous follicles are characterized by 

 their size, 0*5 of a millimeter in diameter, and also by their 

 opening in some instances by free orifices on the surface of the 

 skin. 



Parallel and close to the surface tolerably close plexuses of 

 elastic fibres are stretched, containing regularly arranged 

 smooth muscular fibres (Henle). The papillae, nerves, Pacinian 

 corpuscles, and vessels, are similar to those of other parts of 

 the skin. 



Over that part which is covered by the nymphse the epider- 

 mis becomes somewhat more transparent ; the uppermost cells 

 are still much fused together, though they continue to exhibit 

 well-marked rodlike nuclei. 



The nymphse are invested by a laminated pavement epithe- 

 lium, the lowermost cells of which, in the new-born child, in 



