Manchester Memoirs, Vol. Hi. (igo^), N'o. . y 



duced artificially into any locality may interbreed and 

 produce many intermediate forms. Three* out of the 

 eight were more or less typical AIus rattus rattus — the 

 Mus rattus of Linnaeus, blue-black above and slate-grey 

 beneath, and five* were the brown form, Mus rattus 

 alexandrinus, generally known as the Alexandrine Rat, 

 the Mus alexaiidrinus of Geoffroy — brown on the upper 

 parts and with white bellies. This Alexandrine Rat, 

 though the examples captured could hardly be called red 

 or foxy, is probably the mysterious Red Rat. This species, 

 however, is very variable, and examples from the Medi- 

 terranean basin are usually ruddy : introductions by ships 

 from the Mediterranean might easily be called red. 



We set traps on Rat Island on one day only, but 

 though the majority were sprung we only captured a 

 single example, a large male A/Ius rattus akxandrinus. 

 The general colour of the upper surface of the five 

 examples of AIus rattus akxandrinus, four of which are 

 females, varies from "wood-brown "** to "broccoli-brown" 

 on the flanks, but the brown hair is so interspersed with 

 glossy grey, black-tipped hairs that the whole upper 

 surface has almost a "sepia "or dark brown appearance 

 according to the light. On the flanks the colour is 

 "smoke-grey" with a slight suggestion of "lavender-grey." 

 The bellies, breasts, and underparts generally are whiter 

 in the four females than in the old male, where they have 

 a decided yellowish tinge. 



The general colour of the three darker examples — 



all males of the " Old English " type, Mus rattus rattus — 



is dark "slate-grey" shading into "olive-grey" on the 



belly. There is a suspicion of brown but the black and 



grey hair so predominates that the brown is almost entirely 



* See Table of Measurements at end of Paper. 

 ** The colour terms used are taken from Ridgway's "Nomenclature 

 of Colors," 1886. 



