Abstract
In the glans penis of a dog there is a penis bone covered with a tough periosteum and succeeded by a special connective tissue column at the farther end. The penis bone and the corpus cavernosum urethrae is enwrapped in a connective tissue layer containing aa. et nn. dorsales penis, around which there is my so-called corpus cavernosum cylindricum glandis. Corpus cavernosum apicis glandis takes the place of the former cavernous body at the tip of the glans.
The urethra in glans penis is composed of a stratified columnar epithelium and a fibrous connective tissue propria and has no urethral glands. Corpus cavernosum urethrae is full of longitudinal caverns and contains no smooth muscle fibres. Corpus cavernosum cylindricum glandis is composed of a trough connective tissue and longitudinal caverns running in it in a row, and is devoid of smooth muscle fibres. Around this cavernous body there is a connective tissue layer corresponding to the tela submucosa and the lamina propria composed of minute fibrous connective tissue around it forms minute papillae into the epithelium glandis, which is represented by an uncornifying stratified flat epithelium of mucous nature.
The inner plate of the canine praeputium is a mucous membrane, while its outer plate consists of ordinary hairy skin. The epithelium of the inner plate is represented by a mucosal stratified flat epithelium consisting of larger cells than those of the epithelium of the glans and is thicker than the latter. The lamina propria comprises a part consisting of fibrous connective tissue and another consisting of lymphatic tissue. Small papillae are formed in the former part. Neither gland formation nor existence of smooth muscle fibres is observed in the inner plate of the praeputium. The epidermis of the outer plate of the praeputium is composed of a thin cornifying epidermis and few, if any, papillae are formed into it. Hairs grow in tufts, but the development of the follicle glands is poor. Sweat glands are always apocrine in nature and are extremely well developed. No smooth muscle fibre is found in the outer plate, either.
The vegetative nerve fibres running into the canine glans penis mostly spread out into the corpus cavernosum urethrae and corpus cavernosum cylindricum, but some are conspicuously found distributed in the corpus cavernosum apicis glandis, the lamina propria of the glans and the praeputium. The termination of the vegetative nerve fibres is always represented by the STÖHR's terminalreticulum in canine penis also, reaching as far as the endothelial cells of the caverns in the cavernous bodies. The terminalreticulum is also conspicuously proved around the apocrine and follicle glands.
As corpuscular sensory terminations existing in the canine penis, we may cite the genital nerve and the PACINIAN bodies. Of the former, only the types I and II are observed, the type III being utterly absent. They are found only in a small number in canine penis, incomparably fewer than those in man and pig. Their inner bulbs are characteristically filled with numerous special nuclei. Such genital bodies are seen in the lamina propria of the glans, the connective tissue around it, the corpus cavernosum cylindricum and the inner plate of the praeputium. They are found neither in the papillae nor in the outer plate of the praeputium.
Genital nerve bodies type I are found mostly in the glans penis and more rarely in the inner plate of the praeputium. In a body of this type, two or three demyelinated thick fibres run into the ovoid or spherical capsulated inner bulb, repeatedly undergo ramification and anastomosis and form complex glomerular terminal formation in the whole area of the inner bulb. The genital nerve bodies type II are found in the inner plate of the praeputium in a number, are spherical or ovoid, but very often also elongated cylindrically in shape, and contain inner bulbs in which the sensory fibres end in simple branched terminations.
