222 Mr. E. R. Walte on 



the level of the base of the canine ; posterior palatal vacuities 

 opposite the molars and last two premolars *. Molars small 

 and delicate. 



Dimensions of the type (measured by collector in the 

 flesh) :— 



Head and body 168 niillim. ; tail 120; hind foot 25; 

 ear 18. 



Skull: extreme length 35; greatest breadth 17"8; nasals 

 16x4*2; interorbital breadth 6"3 ; palate length from hen- 

 selion 17*5; breadth at corners of ?n.^ 10; palatal foramina, 

 length 32 ; combined lengths of pm.'^ and ms}~^ [ms}'^ of 

 Catalogue) 5"6. 



Hah. Rio Cauqueta, a tributary of the Cauca, near Cali, 

 Colombia. Alt. 1000 m. 



Type. Male. B.M. no. 99. 9. 6. 51. Original number 470. 

 Collected August 1897 by J. H. Batty. 



This species is evidently a Colombian representative of the 

 Brazilian M. incana and the Venezuelan M. fuscata, but 

 may be readily distinguished from either of them by the 

 characters above given. The three form a special group 

 characterized by tlieir small brain-cases and long narrow 

 unridged interorbital regions. 



XXVIII. — The Oeneric Name Thylacorays. 

 By Edgar R. Waite, F.L.S. 



Mr. T. S. Palmer's paper " On Thylacomys, Owen " f, re- 

 calls my note, published the previous year |, on the spelling 

 of this name, and on its pcssibly jeopardizing a term applied 

 by myself to a new genus of Australian rodents §. In this 

 note 1 mentioned that, not having access to the work in which 

 the name originally occurred — namely, Blyth, in Cuvier's 

 * Animal Kingdom,' 1840, p. 104, — I had referred to the 

 editions of 1819 (p. 104) and 1863 (p. 92), but there found 

 the spelling to be Thalacomys, not Thylacomya. As a result 

 of my note I almost expected that some zoologist in London 

 to whom the 1840 edition is available would have cleared up 

 the matter ; but I have not seen any further reference to it. 



* Accepting the cheek-tooth formula as four premolars and three 

 molars, the third of the premolars being the "z).* " of the Catalogue, and 

 being the only tooth of the " permanent " series (see Lydekker, 1*. Z. S. 

 1898). 



t Palmer, Ann. & Mag. Nat. Hist. (7) iv., Oct. 1899, p. 300. 



I Waite, he. cit. (7) ii., Aug. 1898, p. 196. 



§ Waite, Proc. Roy. Soc. Vict. (n. s.) x. 1898, p. 121. 



