On a new Species of Aconsemys. 281 



Ti/pe. Adult male. B.M. no. 17. 2. 1. 1. Original num- 

 ber 173. Collected 2nd October, 1916, and presented by 

 Rodney C. Wood, Esq. 



This species may be disfin^'ui^lied from ifs only close, 

 tlioiii^h geographically very distant, ally S. alhofuscus hy its 

 smaller size, proportionally even broader skull, and the 

 different shape of tlie base of its canines. The other members 

 of the genus ail have uniformly brown win2;-membranes. 



I may note that of twelve skulls of ScoUecus, including 

 examples of all the described species, only two have com- 

 plete zygomata, although all iiave been prepared by that 

 most skilful skull-cleaner Mr. W. Sherrin. Imperfection or, 

 at least, excessive tenuity of the zygoma would therefore 

 appear to be an additional character of the p^enus Srotfucus. 

 Of forty skulls o'i Scoteinuf similarly prepared by Mr. Sherrin, 

 nearly all have perfect, although very slender, zygomata. 



XXIY. — A new Species of Acousdmys from Southern Chili. 

 By Oldfield Thomas. 



(Published by permission of the Trustees of the British Museum.) 



The British Museum has recently received from IMr. J. A. 

 WolfFsohn a specimen of the rare genus Aconcemys {Schizodon, 

 Waterh.) which had been presented to him by the well-known 

 naturalist Don (>arlos E. Porter. The species proving to 

 be new, I propose to name it in honour of tlie latter, to whom 

 the Museum has been indebted for help in various ways. 



Aconcemys porter i, sp. n. 



Fur more woolly than in A. fuscus; tail more completely 

 bicolor; incisors stouter. 



Size about as in A. fuscus ox rather smaller. Fur soft, 

 more woolly, less straight than in A. fuscus, the general 

 texture and the colour both suggesting that of a European 

 water-vole {Arvicola amphihius). General colour deep rich 

 brown, near " auburn " of Ridgway, the subterminal rings on 

 the hairs dull cinnamon. Under surface similar but vatlier 

 warmer in tone, the etids of the hairs rich cinnamon. Hands 

 and feet greyish white, the middle part of the metatarsus 

 rather darker. Tail rather longer than in A. fuscus and 

 completely bicolor, black above and creamy whitish below for 



Ann. & Mag. N. Hut. Ser. 8. Vol. xix. 19 



