4012 The Zoologist — June, 1874. 



British rat [the snake rat], and I believe them to be identical, though the 

 West-India rats average rather larger size, and are more uniformly of a 

 brown colour. In the British Museum, among tlie stuffed British Mam- 

 malia, is a wretched specimen, wretchedly stuffed, of the new rat, but it is 

 incorrectly labelled ' Mus Rattus,' with which I suspect it has long been 

 confounded. The cranial characters of the two are, however, very different, 

 and these differences are such as are not compatible with mere variety : they 

 are specific" =:= (See Zool. 7232.) 



Surely such a notice from such a man was worthy investigation 

 and preservation in a ' History of British Quadrupeds ;' but I think 

 I am right in saying it is entirely ignored, unless it be alluded lo 

 in the following passage: — "We have seen a few specimens in 

 M'hich the back has been of a dark brownish gray, and their 

 resemblance to the Mus Alexandrinus has been very remarkable ; 

 the lower parts are dark ash-colour, feet and tail dusky." — P. 306. 

 If this be a reference to the snake rat every one of its peculiarities 

 is omitted. 



Before quite dismissing the rats, a question I think may be per- 

 tinent. Have we really two species under the names of black rat 

 and brown rat.^ and what are the diagnostics? Colour will hardly 

 avail. The brown rat has frequently brown and black young ones 

 in the same litter. Then as to a peculiar white mark on the chest, 

 which, in Mr. Thompson's opinion, was sufficient to characterize a 

 species which he called " Mus hibernicus," this mark is occasionally 

 found both in specimens of Mus Hattus and M. decumanus. Again 

 a black variety of the arvicole very familiarly known as the " water 

 mole," is continually occurring, and proves that colour in these 

 rodents is not conclusive. This is another subject on which I wish 

 particularly to invite communications. What are the specific 

 diagnostic characters of our rats ? 



The illustrations do not please me. I admit there is some 

 difficulty in giving an idea of such vast creatures as the Cetacea 

 on so small a scale, and a difficulty also in conveying the idea of 

 a horizontal tail when the animal is drawn laterally ; but there can 

 be no need for placing the tail of Xiphius cavirostris in a directly 

 vertical position, as I have already pointed out, when we all assume 

 that it must be held horizontally by the living animal. 1 say 

 " assume," arguing by analogy : I have never seen it. 



* Italics my owu. 



