MORPHOLOGY OF THE OWLS. 46 



Plate 1. 



Figs. 1-7, dorsal aspect of adult skulls ; 8-14, palatal aspects of adult skulls ; 15 and 16, of young skulls. 

 Fig. 1. Skull of Bubo capensis, showing the forward position of the vestigial supraorbital processes of 

 the frontal. 

 3. Skull oi Bubo perspicillatum, to show the large size of the supraorbital processes. 



3. Skull of Nyctala Tengmalmi, showing the marked asymmetry of the skull in the position of the 



poster bital processes. 



4. Skull of Speotyto ctmicularia, showing large postorbital processes and the temporal fossa 



bridged by the superior angle of the squamoso-occipital wing of the tympanic fossa. 



5. Skull of PhotocUlus badius, showing the great size of the postorbital processes and the backward 



position of the supraorbital processes. 



6. Skull of Strix flammea, showing the absence of supraorbital processes, and the peculiar " dome- 



shaped'" roof. 



7. Skull of Asio accipitriniis, showing an incipient supraorbital groove and peculiar postorbital 



processes, to see which properly a comparison must be made with PI. 2. fig. 2. 



The interest about the supraorbital processes lies in the fact that they are developed by the 

 frontal bone, and not formed by the horizontal process of the lachrymal as in birds generally. 



8. Palate of Bubo capensis, showing large maxillo-palatines and a small vomer. The palatines do 



not quite meet in the middle line. 



9. Palate of Bubo per spicillatum, the vomer has become suppressed ; and the palatines meet in the 



middle line. 



10. Palate of Nyctala Tengmalmi, showing reduced maxillo-palatines ; a vomer ; and the great width 



of the base of the parasphenoidal I'ostrum. 



11. Palate of Photodilus badius, shoyimg ^re&t width of parasphenoidal rostrum; vestigial vomer ; 



and large maxillo-palatines, and lachrymal. 



12. Palate of Strix flammea, showing peculiar shape of vomer; great width of parasphenoidal rostrum 



at base ; and the peculiar shape of the maxillo-palatines. 



13. Palate of Asio accipitrinus, showing swollen parasphenoidal rostrum ; the palatines separated 



one from another posteriorly ; and large maxillo-palatines. 



14. Palate of Speotyto cunicularia, showing maxillo-palatines and absence of vomer. 



15. Dorsal aspect of skull of Syrnium aluco, showing sutures. 



16. Dorsal aspect of skull of Speotyto cunicularia, showing sutures. — Note the great difference in 



the form of the squamosal in the two skulls. 



Plate 2. 



Lateral aspect of the skull. 



Fig. 1. Left side of Nyctala Tengmalmi, to show form of tympanic cavity. — Note the form of the 

 squamoso-parietal wing and contrast with that of right side. For the sake of convenience in 

 comparison the left side has been reversed. 

 1 a. Right side view of same specimen. — Note the form of the squamoso-parietal wing and its 

 relation to postorbital process, and contrast with fig. 1. 



2. Skull of Asio accipitrinus, showing the enlarged tympanic cavity or " cavernum " and the peculiar 



postorbital process. 



3. Skull of Strix flammea, showing the reduced size of the orbit, large lachrymal, and the high 



dome-shaped cranial roof. 

 SECOND SERIES. — ZOOLOGY, VOL. IX. 7 



