MALE ORGANS OF PROBOSCIDIA. 



659 



Protometra of Narwhal. 



CCXXXIX". 





concealed in the prostate, and opening by the usual transverse 



crescentic slit, ib. c, into the urethra, between and a little beyond 



the terminal orifices, ib. b, b, of the sperm-ducts. 



The penis commences by two cavernous crura 



inclosed in strong i erectores,' arising each from 



the loosely suspended ischial ossicle of the same 



side. The crura coalesce into a single cavern- 



- - - o 



ous body surrounded by a very thick sclerous 

 sheath. After the junction of the crura the 

 penis, in Delphinidce, describes a close sigmoid 

 cur-vature, before terminating in the long, 

 straight, gradually tapering glans. The corpus 

 spongiosum commences by a bulbous expan- 

 sion, fig. 518, I, embraced by the 'accelerator 

 fibres,' cj ; but degenerates into little more than 

 a close venous plexus as it penetrates, in the 

 Porpoise, the corpus cavernosum ; it then 

 emerges and extends along the under part of 

 the corpus cavernosum, to re-expand into the 

 venous plexus surrounding the tuberous basis 

 of the glans. The upper part, or dorsum, of the cavernous body 

 is grooved for the lodgment of 

 the plexiform vena dorsalis. In 

 the unexcited state the penis 

 is withdrawn and concealed in 

 the long prepuce, the orifice of 

 which is considerably in ad- 

 vance of the vent. The retrac- 

 tion is effected by a pair of 

 muscles, m, arising from the 

 aponeurotic commissure ante- 

 rior to the sphincter ani e, and 

 running along the under or 

 urethral side of the penis to 

 be inserted into the sclerous 

 basis of the glans. The pro- 

 trusion of the organ is aided 

 by the transverse fibres of the 

 ' panniculus carnosus ' sur- 

 rounding the preputial sheath. 

 The section of the penis of 

 a Balcenoptera preserved by 



Hunter shows a single corpus cavernosum grooved above for the 



uu 2 



Male organs, Phoccena. XII. 





