618 BULLETIN 50, UNITED STATES NATIONAL MUSEUM. 



keel of the sternum; tarso-metatarsus with bony ring or arch to 

 confine the exterior tendon of the toes ; third (middle) toe with its 

 second and basal phalanges subequal; skull relatively broad and 

 short; palatines curved, much wider posteriorly than anteriorly, the 

 maxillo-palatines very broad; prefrontal process of ethmoid consist- 

 ing of a thin plate; interorbital region thin and often perforated.^ 



In addition to the external characters mentioned above, the head 

 is frequently surmounted by a pair of more or less distmct, often very 

 conspicuous, ear- or horn-like tufts of feathers, and the eyes are, as a 

 rule, large and prominent; but there are numerous genera in which 

 these features are not present. 



As in the Tytonidse the Bubonidse have the plumage remarkably 

 full, soft and downy and in coloration more or less "protective," that 

 is to say, characterized by elaborate vermiculation, mottling, etc., 

 though in some the pattern is more bold or simple. The sexes are 

 invariably colored essentially alike. Frequently, as in the case of 

 some Caprimulgi, the plumage is dichromatic, different individuals 

 of the same species, whoUy independent of sex or age, differing 

 remarkably in coloration, the extreme phases being represented by 

 birds of a gray or brownish gray color on the one hand and others of 

 a more or less bright cinnamon-rufous or ''brick-red" hue, individuals 

 of intermediate coloration being usually much less numerous than 

 those representing the extremes. These distmct phases are constant 

 from the first plumage to old age, and are frequently to be found in 

 one brood of young. 



a The genus Phodilus (often referred to the Tytonidse, but now considered an 

 aberrant member of the Bubonidse) presents certain exceptions to the osteological 

 characters given above; and although the discrepancies in question tend toward 

 the characters of the Family Tytonidae they are not, according to Mr. Frank Beddard 

 (Ibis, 1890, 298), sufficiently numerous or important to lead to the conclusion that 

 Phodilus occupies a really intermediate position between the two families, or to indi- 

 cate "the creation of a separate subfamily for its reception, or the amalgamation of 

 the two generally recognized families into one," though it would seem that this 

 conclusion may require reconsideration. 



The characters in which Phodilus agrees with Tyto are the following: 



(1) Absence of extensions over the occipital region of the fossae. 



(2) Comparatively narrow maxillo-palatines. 



(3) Approximately equal width throughout of the palatines. 



(4) Slightly swollen prefrontal process of the ethmoid. 



(5) Comparative thickness of the interorbital septum. 



(6) Absence of bony ring or loop to metatareus (according to Newton, Dictionary 



of Birds, p. 673). 



(7) Absence of manubrial process of sternum (according to Newton). 

 Points of agreement with Bubonidae (Genus Strix) are: 



(1) General configuration and proportion between length and breadth of skull. 



(2) Prominent forehead. 



(3) Absence of occipital convexities. 



(4) Clavicles not united to form a furcula (according to Newton). 



