STEIGES 245 



It is often given as a character of the owls (and as r. bond 

 of union with Pandion) that there is no aftershaft. There 

 is, however, a small one in Strix. As a rule the oil gland 

 is nude, but Nitzsch gives as a constant character of Hybris 

 {= Strix) the presence of two minute feathers upon the apex 

 of that gland; in Asio otu^s too there are two or three small 

 down feathers upon the apex of the oil gland — all of which 

 facts seem to indicate a comparatively recent Joss of the 

 apical tuft so often found in birds. 



The rectrices are invariably twelve in number, except in 

 Micropallas, where there are but ten.^ A singular external 

 character of the owls, carefully gone into by Kaup,^ concerns 

 the asymmetry of the ears ; with this is sometimes corre- 

 lated an asymmetry of the skull in the region of the ear.^ 



The tensores patagii of the "owls ^ are on the whole 

 simple. In none of them is there a biceps slip. Very rarely 

 is there a recurrent tendon uniting the insertion of the 

 brevis with the longus (patagial fan). This occurs, how- 

 ever, in Strix Novcb Hollandia (? always) , S. flammea 

 (occasionally), and S.^ra^inCoZa (? always). Something of 

 the same kind is found in Syrnium aluco, where, however, 

 the connection is between the tendon of the longus, 

 just at its origin, and the inner of the two branches of the 

 brevis. In most owls {Bubo maculosus, Scops leucotis, 

 Pulsatrix torquata, Athene noctua, Strix, Syrnium nebu- 

 losum) the tensor brevis sends off a wrist ward slip not far 

 from insertion of main tendon ; the latter alone crosses the 

 fore arm to be inserted on to ulna. 



In Scops Lempiji, S. Asio, Asio otus, Ketupa javanensis, 

 Otus vulgaris, Bubo ascalaphus, and Nyctea nivea, there is 

 an additional posterior brevis tendon, arising separately from 

 the muscle. This latter tendon sometimes in Otus vulgaris 

 is connected with the middle one. 



' Fide Clakk, ' On the Pterylography of certain American Goatsuckers and 

 Owls,' Proc. U. S. Nal. Mus. xvii. p. 5.51. 



' A monograph of the Strigidse, Zool. Trans, iv. 



" Of. CoLLETT, ' On the Asymmetry of the Skull in Strix Tengmalmi,' 

 F. Z. S. 1870, p. 739. 



■• D'Alton, De Strigum }iusculis Commentatio, Halis, 1837 ; Heusinoeb, 

 Arch. f. Phys. Mil. 1822. 



