176 MAMMALS FROM MOSSAMEDES. 



Euryotis irrorata as a neio specific title to a Rat from the 

 Camerooa Mountains (Burton's collection) and added»! am 

 not certain about this species until I can compare the 

 skull with those of the other species of the genus from 

 Africa, as they are all very similar externally." Perhaps 

 Gray's specimen has nothing in common with the true Eu- 

 ryotis irrorata Brants. 



17. Georychus hottentotus Lesson. 



It may be called a hopeless labor to make out how 

 many species are to be grouped in the genus Georychus , 

 as without exception they have been described insufficiently 

 and mostly figured incorrectly. Only a study of all the 

 types and in the first instance a comparative examination 

 of the skulls , especially of the teeth , may here throw some 

 light. Gray (P. Z. S. L. 1864) divided the species into 

 two groups according to their fur and into four groups by 

 the form (and number) of the grinders. According to Gray 

 Georychus capensis has ~^ grinders, and he thinks that 

 Heliophohius has ^^ grinders, that Heliophohius argenteo- 

 cinereus Peters is his Georychus pallid us , and that the ^~ 

 grinders in Peters' species must have been an anomaly in 

 the type-specimen. (NB. Peters had three skeletons !). As 

 far as I can judge Georychus capensis in a fullgrown state 

 and with a complete dentition has ^^ grinders as well as 

 the other species of the genus, and, as to the number 

 and shape of the molars, Peters' genus Heliophohius is 

 quite distinct from Georychus. In our Museum is one of 

 the types — a rather young stuffed specimen — of Peters' 

 species. The skull was in the skin; I removed it the other 

 day and find 4 grinders in each upper jaw , but 5 in each 

 lower jaw. My specimen measures 120 m.m. and Peters' 

 type 185 m.m., and it therefore is clear why in my spe- 

 cimen all the grinders are not yet developed. Peters was 

 quite right, for my young specimen again demonstrates 

 that, although externally there are no generic differences. 



Notes from tlie I-ieyden IMuseum, "Vol. IX. 



