

MALE ORGANS OF MARSUPIALS. 645 



evinced in its bifurcation, corresponding with that of the glans 

 itself. That the existence of a penis is essentially related to the 

 s exua l organs and not to the renal, is singularly illustrated by 

 the complete separation of the uro-urethral from the semino- 

 urethrai passages in Monotremata. The modifications by which 

 the male organs in the Echidna differ from those of the Orni- 

 thorhynchus, are confined to the glans penis, which divides into 

 four mammilloid processes, roughened by minute papilla?, and 

 terminated by a depression in which is the branch of the seminal 

 canal that traverses each process. Cowper's glands, fig. 3, k, k, 

 and fig. 502, h, are of large relative size; they are situated between 

 the base of the penis, the arch of the ischium, and internal part 

 of the thigh : their secretion is carried by a long and slender 

 duct, ib. m, into the seminal urethra. The physiological relation 

 of these glands to such a canal is clearly illustrated by their 

 presence in the Monotremes, and by their absence in the oviparous 

 animals which have merely a seminal groove. There are neither 

 prostatic nor vesicular glands. It is probable that the spurs, in 

 the male Monotreme, fig. 500, e, may relate to the sexual act, as 

 holders or stimulators. 



> § 370. In Marsupialla. — In these Lyencephala the testes, which 

 are still abdominal at the time of birth, descend, soon after the foetus 

 is transferred to the pouch, into the external pedunculate pre- 

 penial scrotum ; the canal of communication between the abdo- 

 minal cavity and the tunica vaginalis is long and narrow, but 

 always remains pervious. The tubuli testis are relatively 

 smaller than in Monotremes, but the corpus Highmori is near the 

 surface and upper part, not at the centre, of the gland. The 

 epididymis is large, and generally loosely attached to the testis. 

 The spermatozoa of the Perameles have a single barb at the base 

 of the head, which is sub- elongate and compressed ; in other 

 respects, as in size and proportion of the filamentary tail, they 

 resemble those of the Rabbit. Neither in the Kangaroo, Pha- 

 langer, nor Dasyure do the spermatozoa present a spiral head or 

 any noticeable deviation from the characters of the spermatozoa 

 in the smaller placental quadrupeds : those of the Dasyure have 

 a node at the base of the head. The spermduct passes along the 

 infundibular muscular sheath formed by the cremaster as far as 

 the abdominal ring, then bends downward and backward, external 

 to the ureter, and terminates, fig. 503, a, at the commencement 

 of the urethra, at the side of a longitudinal verumontanal ridge. 

 There are no vesicular glands. 



As the part of the urethral canal immediately succeeding the 



