MORPHOLOGY OF THE OWLS. 41 



b" . Squamosal wing of tympanic with broad rounded lateral border, projecting 

 considerably beyond base ol: postorbital processes ; pterygoid sigmoidally 

 curved ; tympanic cavity very large and bullate, extending upwards 

 and backwards to underlie the floor of the temporal fossa ; palatines 

 nearly touching caudad Carine. 



c". Squamosal wing of tympanic projecting but slightly or not at all beyond 



base of postorbital process Glaucidium *. 



B. Vertebrae. 



All the presynsacral vertebrEe are free and heterocoelous ; the last thoracic is included in the synsacruni. 

 Innominates fused with synsacrum. The centra of the thoracic bear more or less conspicuous pneumatic 

 apertures opening beneath the transverse processes. Only the 2nd to 5th and the 14th bear neural 

 spines. The cervical ribs of all save the 13th and 14th vertebrse are very short or vestigial ; the 13th 

 and 14th ribs are free, and the 14th may bear uncinates ; the eatapophyses never meet to form a canal. 

 The fovea lumhalis ischiadica and pudendalis are all well defined, and thereby the vertebral column 

 may be readily distinguished from that of the Caprimulgi ; but there seems to be no character of 

 universal application by which the vertebral column of the Striges may be distinguished from that of 

 the Falconiformes, when birds of a similar size are being compared. The distinctions between the 

 vertebrae of the two families of the Striges and the various genera thereof are very slight. 



a. Neural spines high, sloping forwards and interlocking. 



a'. Transverse processes of thoracic vertebrae with anterior and posterior angles 



produced into lateral spinous processes ; hypapophyses long, not extending 



beyond 2nd thoracic. 



a". Preacetabular ilium with dorsal border nearly straight ; ventral border deeply 



emargiuate ; preacetabular width nearly equal to width across ■ anti- 



trochanter Asio. 



b". Preacetabular ilium with dorsal border nearly straight ; ventral border 

 gently hollowed ; preacetabular width much less than width at anti- 



troehanter Bubo. 



(•' . Preacetabular ilium with strongly arched dorsal crest ; ventral border 

 deeply hollowed ; preacetabular width equal to width across auti- 



trochanter Ketupa. 



b'. Transverse processes without spinous lateral angles ; hypapophyses long, 

 extending to 3rd thoracic ; lumbar vertebrae 4 ; lumbar parapophyses 1-2 

 vestigial ; ji/aiium cocci/r/cum wanting Carine. 



b. Neural spines high, nearly vertical and feebly interlocking. 



Hvpapophyses short, not extending beyond the 2nd thoracic; 4 lumbar vcrtcbrjc; 

 roof of fovea pudendalis not o\)>itn\ctcd by parapophyseal processes; a con- 

 spicuous idainim coccijijcuiii Si/rniiim. 



c. Neural spines high, not interlocking; hypapophyses short, not extending beyond 



1st thoracic ; 3 lumbar vertebr;e Ninox. 



d. Neural spines low, interlocking. 



a'. Hypapophyses long, spine-like, extending back to 3rd thoracic ; planum coccy- 

 geuni indistinct. 



* For remarks on Glaucklmm, sec p. 36. 

 SECO>"D SERIES. — ZOOLOGY, VOL. IX. 6 



