EXTERNAL CHARACTERS OF MONGOOSES. 371^ 



side of the depression there is a small supplementary pouch a 

 little higher up than the anus. In the middle line of the sac, 

 nearly midway between the anus and the root of the tail, there 

 is a moderately large unpaired supplementary pouch, and on each 

 side of this, but a little lower down and about half-M'ay between 

 the anus and the margin of the sac, there is another moderately 

 large pouch. The orifices of the anal glands open just below 

 these in a line with the anus, but outside the central depression 

 in which the anus lies. Thus the anal sac of Helogale approaches 

 that of Suricata, and differs from the sac of any species of 

 Mungos I have examined. 



Function of the Anal Sac. 



On the material at my disposal I was unable to substantiate a 

 higher grade of development of the anal sac and its associated 

 glands in the male than in the female, or vice versa. On the 

 evidence, therefore, this composite glandular structure cannot be 

 included in the category of sexual organs except on the plea that 

 the secretions may help the sexes to find each other. 



Captive Mongooses have the habit, also observed in Genets 

 and Civets, of rubbing the glandular surface against the walls or 

 projecting angles in their cage or against the legs of chairs and 

 tables in a dwelling-room. Hence it ma}'- be inferred that one 

 of the functions of the secretion is to make the animal's sur- 

 roundings smell of itself, and the scent so applied serves, I 

 believe, the purpose of familiarising the Mongoose with every 

 square yard of its environment, so that, independently of vision, 

 if need be, it can find its way with precision over any road it has 

 once travelled *. 



Several of the Mongooses, too, like Cynictis, Suricata, Ariela, 

 and Helogale are gregarious t ; and of one species of Helogale at 

 least the habit of hunting in packs has been recorded. One of 

 the larger Indian species of Mongoose {M. vitticoUis) t has been 

 seen combining in pairs in pursuit of prey. And since specialised 

 cutaneous glands very often attain exceptional development in 

 gregarious animals for the purpose, presumably, of helping indi- 

 viduals to keep together, it is not imjDrobable that the secretion 

 of the glandular anal sac has a functional significance in that 

 respect in some of the Mongooses. 



Finally, Hodgson's record § that the • secretion of the paired 

 anal glands in Mungos urva is " aqueous, horribly foetid, and 

 projectile to a great distance by the living animal," suggests that 



* It is well known that most mammals have the habit of keeping to definite 

 beaten tracks. The advantage of this to species like rats and rabbits is verj' evident. 

 I have frequently seen rats escape from dogs by knowing exactly the position of a 

 pipe or of a hole in a wire-net fence. They make a bee-line for the spot at full 

 speed, and, apparently without ever seeing the hole, go straight through it, knowing 

 the precise direction to take by complete familiarit}' with the track, owing, I believe, 

 to the scent it holds. 



t See W. L. Sclater, ' Fauna of S. Africa ' : Mammalia, vol. i. p. 69, 1900. 



X Quoted hy Blanford, ' Fauna of Brit. India ' : Mammalia, p. 129. 



§ Journ. As. Soc. Bengal, vi. pt. ii. p. 563, 1837; also my paper in Ann. Mag. 

 Nat. Hist. (8) viii. p. 756, 1911. 



Proc. Zool. Soc— 1916, Xo. XXY. 25 



