MALE ACCESSORY REPRODUCTIVE ORGANS 247 



In anofcher rodent, the marmot, according to Gilbert^ the 

 skin which covers the os penis becomes torn away during the 

 rutting season, so that the bone projects freely beyond the end 

 of the glans and is then used as a stimulating organ. 



Structures which project from the penis, and are probably 

 employed as sexual irritants, are also found in the rhinoceros, 

 the tapir, and certain other animals. 



In the cat the glans is beset with callous retroverted papillae, 

 which no doubt serve the same function. They are present also 

 in the lion and tiger, but are of smaller size.^ 



Perhaps the most curious modifications presented by the 

 mammahan organ of copulation are those found in certain 

 species of Ruminants. In the sheep, the gazelle, the giraffe, 

 and a number of antelopes, there is a long filiform process 



Fig. 61. — Distal end of ram's penis, as seen from the left side, showing 

 glans and filiform appendage. The prepuce is folded back. Slightly 

 reduced. 



attached to the end of the organ and traversed by the urethral 

 passage. In some forms the process arises medially (the penis 

 being symmetrical) ; but in others, such as the sheep, it is 

 attached to the left side of the organ, the distal end of which 

 appears to have undergone some sort of torsion.^ The urethra 

 opens to the exterior at the extreme end of the filiform ap- 

 pendage. This structure — which has been investigated, especially 

 in the case of the sheep *— is composed largely of erectile tissue 

 which surrounds the urethra, and may be regarded as an ex- 

 tension of the corpus spongiosum. Outside the erectile tissue is 

 a weU-marked muscular layer which lies next to the integument. 

 The process is supported by a pair of fibro-cartilage bodies, 



' Gilbert, " Das Os priapi der Saugethiere, " Morph. Jahrbuch, vol. xviii. 



" Owen, On the Anatomy of Vertebrates, vol. iii., London, 1868. 



' Garrod, "Notes on the Osteology and Visceral Anatomy of Ruminants," 

 Proc. Zool. Soc, vol. xlv., 1877. 



* Nicolas, "Sur I'Appareil Copulateur du B^lier,'' Jour, de I'Anat. et la 

 Phys., vol. xxiii., 1887. Marshall, "The Copulatory Organ in the Sheep," 

 Anat. Anz., vol. xx., 1901. 



