DEVELOPMENT OF THE SKULL IN THE OSTRICH TRIBE, 183 



Fig. 4. End view of skull ; 2 diameters. 



Fig. 5. Side view of skull from within ; 2 diameters. 



Fig. 6. Side view of skull of do. with the outer part pared away to show the structures 



of the internal sac; 4 diameters: c.li.l. cochlea; c.f. cerebellar fossa. 

 Fig. 7. Transversely vertical section of skull of C. Bennettii, seen close behind the lateral 



ethmoids; 2 diameters. 

 Fig. 8. A similar section through the interorbital space ; 4 diameters. 

 Fig. 9. Horizontal section through the left pars plana with its middle turbinal tent ; 



8 diameters. 

 Fig. 10. Another section at the lower part of the turbinal, showing a bifurcation of the 



turbinal outgrowth ; 8 diameters. 

 Fig. 11. A similar section a line lower down than fig. 9, showing the anterior opening into 



the tent; 8 diameters. 

 Fig. 12. Os hyoides of C. Bennettii ; 2 diameters. 



PLATE XV. 



Fig. 1. Side view of skull of Tinamics variegatus, adult (4th year) : s.o.h. superorbitals ; 

 2 diameters. 



Fig. 2. Basal view of skull ; 2 diameters. 



Fig. 3. Upper view of skull ; 2 diameters. 



Fig. 4. Part of fig. 2; 4 diameters; showing the anterior sphenoid and its surroundings : 

 f. orbital plate of frontal. 



Fig. 5. Tinamus robustus, adult. Inside of anterior -part of skull; 4 diameters. 



Fig. 6. Tinamus robustus, part of the face seen from above; 4 diameters: j).2>.v. prox- 

 imal process of prevomer. 



Fig. 7. Tinamus robustus, side view : p.x. angle of premaxillary. 



Fig. 8. Tinamus robustus, part of ethmoid and nasal septum, side view ; 4 diameters : 

 c.f.c. rudiment of cranio-facial cleft. 



Fig. 9. Section through fullest part of the inferior turbinals of Tinamus variegatus ; 

 6 diameters. 



Fig. 10. Another section further forwards ; 6 diameters. 



Fig. 11. Another through the alse nasi, and in front of the septum nasi; 6 diameters. 



Fig. 12. Os hyoides of Tinamus variegatus ; 2 diameters. 



Fig. 13. Tinamus variegatus, adult. Side view of nasal structures, with the lateral bones 

 removed; 4 diameters. 



Fig. 14. Inferior turbinals of Psophia crepitans without the prepalatine splints ; 4 dia- 

 meters. 



