1908.] IN^ THE MUSTELINE CARXI^ORA. 95o 



diet of Grisons is mixed. Two now living in the Zoological 

 Gardens feed upon fowls' heads, dried dates, and bread and milk. 



The so-called Patagonian Weasel {Lyncoclon patagonicus)^ 

 although smaller than the Grison, presents much the same style 

 of coloration. The hair of the body and tail is long and grey. 

 On the nape of the neck there is a large black patch which 

 emphasises a large white patch covering the top and sides of the 

 head and extending laterally along the neck. This is set off both 

 in front and below by the black colour of the muzzle, cheeks, 

 sides of the neck, and lower shoulder. The legs are black. Yery 

 little seems to be known of the habits of this animal. It may or 

 may not be offensive like the Grison. If it is, its coloration is, I 

 think, probably genuinely aposematic. If it is not, the resem- 

 blance in colour between the two may be an instance of true or 

 Batesian mimicry. The evidence, however, that the two species 

 are found together is not conclusive. In favour of this view it 

 may be added that Lyncoclon has been recorded in Central 

 Argentina from Mendoza and Azul southwards to the Rio Colorado 

 and Rio Negro, and Grison also as far south as the Rio Colorado * ; 

 a,nd according to Trouessart's Catalogue both occur in ISTorthern 

 Patagonia. 



Bat exact coincidence in distribution is not essential to the 

 belief that the resemblance between the two animals is an instance 

 of Batesian mimicry or of Miillerian resemblance. It is merely 

 essential to show that enemies that might prey upon small 

 carnivora of this kind are dispersed over the areas inhabited by 

 the two forms. Wide ranging raptorial birds, for example, that 

 knew the Grison by sight in the northern parts of La Plata, 

 might easil}^ mistake the Patagonian Weasel for the young of it 

 in the southern parts of that country. 



An interesting parallel is traceable between Lyncoclon and 

 Grison in South America, on the one hand, and Pmcilogale and 

 Ictonyx in Africa, on the other. In both cases, we have a large 

 musteline which is known to have offensive stink-glands, and a 

 smaller one in which this attribute has not yet been recorded. 

 There are reasons for thinking that in both the larger species 

 the coloration, though widely different, is aposematic; and the 

 smaller form in each case resembles the coloration of its com- 

 patriot. The smaller forms also appear to be much scarcer than 

 the larger, a fact which is in favour of their coloration being 

 mimetic. 



Singularly enough, too, Lyncoclon and Poecilogcde resemble each 

 other and differ from typical mustelines, including their hypo- 

 thetical models, in the reduction of the number of cheek-teeth 

 to three on each side in both the upper and the lower jaws, the 

 total number of teeth being 28. In both Ictonyx and Grison, 

 on the contrary, there are four cheek-teeth in the upper jaw and 

 five in the lower, making a total of 34. 



* Matschie, SB. Gcs. nat. Fr. Berlin, 1895, p. 190. 



