SECT. 201.] MALE SEXUAL ORGANS. 447 



composed of transversely striped and smooth muscular fibres. The 

 testicle obtains its proper tunica vaginalis by the growing together 

 of the processus vaginalis with its own serous covering. The 

 vesicula prostatica, the analogue, in man, of the uterus, and per- 

 haps, also, of the vagina, is all that remains of the ducts of 

 Muller, two canals, which descend at the external border of the 

 Wolffian bodies. In the female, these canals form the Fallopian 

 tubes, and at their lower extremities, where they coalesce, they 

 become developed into the uterus and vagina ; but, in man, they 

 disappear, except at the lowest part and at the commencement, 

 which is converted into the ' hydatid of MorgagnV The vas 

 aberrans, and the similar structure at the head of the epididymis 

 (sec my Mier. Aunt., ii. 2, p. 392), are the remains of those other 

 tubules of the Wolffian bodies which have not become connected 

 with the testicles ; these are frequently converted into cysts which 

 contain semen, and are named by Luschka ' non-pedunculated 

 hydatids of MorgagnV The seminal vesicles are hollow protru- 

 sions from the vasa deferentia ; while the prostate, the glands of 

 Cowper, and the smaller glands, are, in all probability, developed 

 from the epithelium of the urethra, in an analogous manner to 

 other glands of a similar character. The penis is developed out- 

 wards from the pelvic bones, and, subsequently, receives the urethra 

 by the closure of a groove at its lower side. 



Very little is known about the histological development of these 

 parts. The testicles consist, at first, of an uniform mass of cells, 

 which soon, however, exhibit variety of structure in transverse 

 rows, that form the rudiments of the seminal tubules. These are, 

 at first, straight canals, extending from the outer to the inner 

 border of the testicle, and terminating in caecal processes; and it 

 is extremely probable that they originate as solid strings of cells, 

 and, subsequently, receive a cavity and a membrana propria. By 

 continued growth, especially in the longitudinal direction, and by 

 the formation of processes, these primitive ducts become eventually 

 the extremely long and convoluted seminal tubules ; indeed, an 

 entire lobule appears to be formed from each of them. 



I may here draw attention to one or two points in the physiology 

 of the male sexual organs. The spermatozoa are now universally 

 understood to be no animalcules, but elementary portions of the 

 male organism. We do not understand, however (and it will pro- 

 bably long remain obscure), the mode of production of their very 

 curious movements ; the object of their motion is evidently to 

 propel them onwards from the uterus (which they probably reach 



