BIRDS OF NORTH AND MIDDLE AMERICA. 599 



Sternum without manubrium, the metasternum entire or else witii 

 but one notch on each side.; clavicles united, forming a furculum, 

 and solidly joined to the keel of the sternum; tarso-metatarsus with- 

 out a bony ring or arch over the extensor tendon of the toes; third 

 (middle) toe with second phalanx decidedly longer than the basal 

 phalanx; skull relatively long and narrow, with palatines nearly 

 parallel to each other, approximately the same width throughout, 

 almost concealing the maxillo-palatmes, which are broader from 

 above downward than from side to side; prefrontal process of eth- 

 moid consisting of rounded bones of some width; interorbital region 

 not forming a thin plate anteriorly, but of considerable thickness. 



The pterylography is thus described by Mr. Hubert Lyman Clark: « 



"The head is more uniformly feathered above ^ and shows no 

 signs of longitudinal rows, but the infra-mandibular region is scarcely 

 feathered at all, excejDt for the very narrow lower cervical tract, 

 which begins at the base of the gonys and extends nearly to the furcula 

 before forking widely. It is, however, slightly divided for some dis- 

 tance before it actually forks, so that the upper part of each branch 

 is abruptly wider than the lower, although there is no true inner 

 branch given off. The upper cervical tract is very narrow, whOe the 

 humerals are narrower than in any other genus, and the parapterum 

 is weak. The femorals are strong, but very diffuse, and are scattered 

 over most of the femur. The feet are not feathered quite to the toes, 

 but the latter are very hairy, the sternal tract is fused with the ven- 

 tral, not only at its origin near the furcula, but also at the other end 

 of the breast, so that the tracts are really one; very broad on the 

 sternum, and containing a longitudinal apterium, and becoming 

 abruptly narrow on the belly. The hypopterum is very strongly 

 marked, and the hook connecting it with the sternal tract is com- 

 posed of larger feathers, and they are much more numerous than in the 

 other owls. Indeed, the whole breast is much more thickly feathered 

 than in Asio. Another remarkable peculiarity is the formula for 

 the comparative lengths of the rectrices. In all the other owls the 

 middle pair of tail feathers is the longest and the external pair short- 

 est, so that the formula is 1, 2, 3, 4, 5, 6. In Strix [i. e., Tyto], how- 

 ever, this is exactly reversed, the outer pair being the longest and 

 the formula reading 6, 5, 4, 3, 2, 1. There are fifteen secondaries 

 and the primaries rank as follows : 9, 8, 10, 7, 6, 5, 4, 3, 2, 1, 11." 



This family includes a single genus. <= Phodilus Isidore-Geoffroy 

 was formerly included, on account of its superficial resemblance to 

 Tyto, but has since been found to more nearly agree structurally with 



a Proc. U. S. Nat. Mus., xvii, 1895, 565. 



b As compared with that of Asio wilsonianus and other Bubonidse. 

 c The fossil (extinct) genus Badiostes Ameghino is placed in this family by Dr. 

 Sharpe (Hand-list, i, 1899, 302). 



