ECEXT-GLANDS IN MAMMALS. 747 



the median aperture opens in the dorsal wall of the prepuce. 

 I have examined this glaiid in Stis scrofa ; but its presence or 

 absence in other genera and species of Suidse has yet to be 

 established. 



In S'us scrofa also there is a subvertical series of small glands 

 on the. postero-inner side of the carpus and known as the carped 

 glands. The carpal and preputial glands have long been known 

 in domestic swine, the carpal glands being present both in boars 

 and sows. 



Digital Glands 0/ Potamochoerus. — These glands, which do not 

 appear to have been previously recorded, I discovered on the fore 

 and hind feet of a male example of the South African River-hog 

 or Bush-pig {Potamochoerus clueropotamus), which died in the 

 Gardens, Oct. 30th, 1911. 



On the fore foot there is a pair of these glands, one of them 

 opening upon the skin of the lower side of the second digit, a 

 little above the base of the hoof, and the other in a Corresponding 

 position on the fifth digit. Each is marked externally by a small 

 pore with a thickened circular rim. The sac of the gland, filled 

 with white, waxy secretion, is tolerably capacious and flask- 

 shaped, the neck of the flask being represented by a short, 

 narrow duct leading to the pore and bent nearly at right angles 

 to the long axis of the gland, which projects upwards within the 

 digit. By pressure the secretion can be squeezed fi'om the orifice 

 of the gland. 



The hind foot has two precisely similar glands on the second 

 and fifth digits and, in addition, a third unpaired gland nearly 

 resembling them and opening in the centre of the sole of the 

 foot, a short distance behind the cleft between the second and 

 thii-d digits. The flask-shaped sac of the gland, filled like the 

 others with waxy secretion, lies in the foot between the bones of 

 these digits. 



I do not know whether these glands are confined to the male 

 or not ; but no trace of them was to be discovered in a young- 

 female of the West African species (P. jJorcus). Seeing that two 

 distinct species are here concerned, it is clearly impossible to 

 draw any sure conclusion as to the absence of these glands in the 

 female of F. choei-opotamus and to their presence in the male 

 of P. porous. Nevertheless, the constancy in the occurrence of 

 similar glands in nearly related species of ruminant Artio- 

 dactyles justifies, by analogy, the expectation that these digital 

 glands will be found to be a secondary sexual character confined 

 to the male in the genus Potanwchcerus. 



The Metatarsal Glands of Lama vicuna. 



On each side of the metatarsus Llamas hiixe an elongated naked 

 patch of skin with which everyone who has kept these animals is 

 probably acq ua i n ted . 



In a female example of La,via vicuna this area. ])ijik in colour 



51- 



