On a new Species of Acontemys. 281 



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

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

 Rodney 0. Wood, Esq. 



This species may be distinf^uished from its only close, 

 though geographically very distant, ally S. albofuscus by its 

 smaller size, proj)ortionally even broader skull, and the 

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

 of the genus all have uniformly brown wing-membranes. 



I may note that of twelve skulls of Scotcecus, including 

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

 plete zygomata, although all have 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 genus Scotcecus. 

 Of forty skulls of Scotei'ma similarly prepared by Mr. Sherrin, 

 nearly all have perfect, although very slender, zygomata. 



XXIV. — A new Species of Acousemys from Southern Chili. 

 By Oldfield Thomas. 



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



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

 "Wolffsohn a specimen of the rare genus Aconcemijs {Schizodon, 

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

 naturalist Don Oarlos E. Porter. The species proving to 

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

 the Museuui has been indebted for help in various ways. 



Aconcemys porteri, sp. n. 



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

 bicolor; incisors stouter. 



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

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

 texture and the colour both suggesting that of a European 

 water-vole [Arvicola amphibius). General colour deep rich 

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

 the hairs dull cinnamon. Under surface similar but rather 

 warmer in tone, the ends 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 

 com |)letely bicolor, black above and creamy whitisii below for 



Ann. ifc Mag. iV. Hist. Ser. 8. Vol. xix". 19 



