48 On the Pterylography of Photodilus. 



d'. Membranous aperture of ear variable in size, but 



its vertical axis never exceeding the horizontal 



axis of the eyelid; aperture not closed by an 



operculum. 



a". Oil-gland conical; cere not inflated, but closely 



investing the base of the beak; posterior 



half the height of the anterior division of 



the cavernum Bubo. 



b". Cere laterally inflated ; anterior and posterior 



divisions of the cavernum of equal height. . Scops. 



Nino.v. 

 Sceloglau.r. 



V. Titles of the Papers referred to. 



1. Beddard, F. E. On Photodilus hadius, with Remarks 



on its Systematic Position. Ibis, ser. 6, vol. ii. p. 239 

 1890. 



2. Nitzsch. Pterylography. English Transl. 1866. 



3. Pycraft, W. P. A Contribution towards our Knowledge 



of the Morphology of the Owls. Trans. Linn. Soc. 

 2nd ser. Zool. vol. vii. 1898. 



VI. EXPLANATION OF FLATE II. 



Fig. 1. Left side view of the head of an adult Photodilus badius, to shew 

 the form of the external ear. This should be compared with tig. 2 — 

 the right side of the same head — to shew the asymmetry of the two 

 sides. 



a.e. = externa] aperture of ear. 



a.c. = apterium capitis. 



e. = eye. 



f. = fossa — the deep trench below the aperture of the 



ear. 

 p.f. = the cut bases of the peripheral disc-feathers, 

 seated in a feebly developed postaural fold. 

 pt.coll.vent. = pteryla colli ventralis. 

 Fig. 2. Right side view of the same head. Letters as before. 



Fig. 3. Back view of the same head, to shew the different levels of the 

 right and left external apertures of the ear and the form of the 

 apterium capitis. 



r.a.e. = right aperture of ear. 

 l.a.e. — left ,, „ 



pt.coll. = pteryla colli dorsalis. 

 pt.cap. = ,, capitis. 



