AVES. 51 



(2. PERNIS.) Lore closely covered with small scaly feathers: tarsi 

 moderate, half-feathered; acrotarsia reticulated. 



(3. CIRCUS.) Sides of the head furnished with a circle of feathers 

 approaching that of the owls : tarsi elongated, feathered a little 

 helow the joint; acrotarsia scutellated : tail long; somewhat 

 rounded. 



III. STRIGID^E. Head large, feathered ; base of 

 the bill clothed with stiff bristly feathers directed 

 forwards, concealing the cere and nostrils : eyes 

 surrounded by a circle of radiating feathers : 

 legs feathered to the toes: outer toe reversible. 



7- BUBO Bill strong, bending from the base : nos- 

 trils oval or rounded : facial disk small and incomplete : 

 auditory aperture small, oval, without an operculum : head 

 furnished with large conspicuous egrets: wings moderate; 

 third quill generally the longest, 



(1. BUBO.) Legs rohust, feathered to the claws. 



(2. SCOPS.) Tarsi feathered : toes naked. 



8. OTUS Bill bending from the base : nostrils oval, 



oblique: facial disk complete, of moderate size: auditory 

 conch large, the aperture covered by an operculum : egrets 

 more or less conspicuous : wings long ; second quill longest : 

 legs feathered to the claws. 



9. STRIX Bill somewhat elongated, bending at the 



tip only : nostrils oval : facial disk complete and full-sized : 

 auditory aperture large, furnished with an operculum : head 

 without egrets : wings long ; second quill longest : tarsi 

 feathered : toes hairy ; middle claw serrated beneath. 



10. SYRNIUM Bill bending from the base: nos- 

 trils round : facial disk large and complete : auditory 

 aperture large, furnished with an operculum: head with- 

 out egrets : wings short and rounded ; fourth and fifth 

 quills longest : legs feathered to the claws. 



11. NOCTUA. Bill bending from the base: nos- 

 trils oval : facial disk small, and generally very incom- 



D2 



