276 M. F. Pollen on the Genus Oxynotus. 



only on my visit to the Museum at the Royal College of Port 

 Louis that I first had the pleasure of seeing one. 



Thanks to the kindness of Mr. Bouton, I had the opportunity 

 of examining examples of the Mauritian Oxynotus, and of com- 

 paring them with those of Reunion. I was then convinced that 

 the remarks of the Editor of 'The Ibis ' were exact and correct, 



1 may here state that M. Jules Verreaux, in the '' Annexe " to 

 M. Maillard's ' Notes sur File de la Reunion'"^, says (p. 162), 

 " TuiTUiT. Oxynotus ferrugineus, Sw. (Lanius ferrugineus, 

 Gm.). Oiseau decrit sur la femelle, qui est rousse, le type 

 venant de File Maurice " ; and also remark that the Colonial 

 Museum at St. Denis possesses a specimen of the Reunion bird, 

 determined by this learned ornithologist to be a young male of 

 O. ferrugineus, whereas I am now sure that it is an adult female 

 of what I am about to describe as a new species; for, on com- 

 paring examples of Oxynoti from the two islands, I find such 

 differences of size and colouring between them as to lead me to 

 believe that they do not belong to the same species ; and when 

 we know that these differences are constant, so that in Reunion 

 an Oxynotus has never been found with the form and colour of 

 that of Mauritius, nor in Mauritius has there ever been found an 

 Oxynotus like that of Reunion, we must conclude that the birds 

 of the one island are distinct from those of the other. 



The following Table shows the relative proportions of the 



birds of both islands : — 



Mauritius. Reunion. 



Long, tot 175 mm. 190 mm. 177 mm. 177 mm. 



„ tarsi 23 26 24 25 



,, dig. med. sine ungue 16 16 15 15 



„ mandib. sup 30 28 20 20 



„ alffiacarp 100 104 95 94 



„ caudffi 82 87 90 87 



From this it is apparent that the Mauritian Oxynotus exceeds 

 that of Reunion in a majority of the above dimensions. 



The males of the Mauritian species have the upper part of the 

 head, back, and rump of a dark smoke-grey, in immature (?) 

 specimens slightly tinged with rufous. The chin and throat 



* [Cf. Ibis, 1863, pp. 103, 104.] 



