Pterylography of Photodilus. 47 



narrower median branch of the pt. centralis and in the 

 extension upwards to the crown of the head of the apt. 

 trunci laterale. In the latter respect it agrees with Bubo 

 maculosus . 



I do not propose to enter further upon the discussion of 

 the question of the systematic position of Photodilus at the 

 present time, as I hope to return to this subject in a future 

 paper, wherein the osteology and the anatomy of the soft 

 parts will be dealt with, together with a general summary of 

 the literature of the subject. I will only remark that, as 

 Beddard. has already conclusively shown, Photodilus is not a 

 near ally of Strix, as has been contended on more than one 

 occasion. 



IV. Revised Key to the Subfamilies and Genera of the 

 Family Asionidse. 



The remarkable character of the external ear of Photodilus 

 has rendered necessary a slight revision of the first portion 

 of the "Key to the Families, Subfamilies, and Genera" 

 given in my former paper (3). 



The revised portion stands as follows : — 



A. The median branch of the ventral tract free posteriori}- ; 

 the feathers of the hinder border of the acrotarsium 

 directed downwards ; no tiloplumes at the end of 



the oil-gland I. Asionid.e. 



a. Interscapular region of pt. spinalis with a long 



bifurcation Subfamily 1. Asionince. 



a. Membranous aperture of ear of great size, ex- 

 tending from gape backwards, upwards, and 

 forwards to terminate above the middle of eve ; 

 aperture covered with a large operculum and 

 divided into upper and lower moieties by a 



fleshy fold Asio. 



b'. Membranous aperture of ear large, but its vertical 

 axis not exceeding the horizontal axis of the 

 eyelid ; aperture closed by a large operculum 



and not divided by a fleshy fold Syrnium. 



c . Membranous aperture of ear small, oval, that of 

 right side bounded above, and that of left side 

 below, by a deep crescentic channel ; aperture 

 not closed by ar. operculum Photodilus. 



