b PICO-PASSERES. 



Trypanocorax frugilegus. 



12. Skull with lower jaw attached. The boiij' siphonium, which 



conducts the air from the tympanic cavity to the articular 

 bone, is indicated on the left side by black paper. The 

 ligaments are painted blue. Preseiited Inj Lord Lilford. 



13. Skull. Hed bristles have been passed through the siphonia 



into the tympanic cavities. The right membrana tym- 

 pani has been removed. A red bristle has been passed 

 into the opening in the left articular, through which air 

 enters the lower jaw. Presented by Lord Lilford. 



14. Skull. The bony siphonia have been left attached to the 



articular bones. Presented hy Dr. D. Sliarp, F.R.S. 



15. Hyoid. The entoglossal is represented by a paired bone. 



Presented by Br. D. Sharp, F.R.S. 



16. Sternum and shoulder-girdle. 



Presented by Dr. D. Sharp, F.R.S. 



17. Pelvis with adjacent vertebrae. 



Presented by Dr. D. Sharp, F.R.S. 



Genus CORVUS*. 

 Liiinieus, Syst. Nat. ed. 12, i. p. 15-5 (1766). 



Corvus corax. 



Liiiiiieiis, loc. cit. ; Eyton, Ostcol. Av. p. 14-5 ; Sharpe, Cat. B. 

 Erit. Mu8. iii. p. 14 (1877). 



The Common E/Aven. 



Hab. Europe and Northern and Central Asia, .North America, 

 as far south as Mexico. The Raven of the Old and New Worlds 

 is practically the same bird, but varies considerably in size in 

 various localities. On the variation in the size of skulls in 

 Eavens from Alaska and New Mexico, with figures, cf. Shufeldt, 

 Proc. U.S. Nat. Mus. 1887, p. 38G. 



* The slieleton of Vvrvus sccqiuhitus is tiii-uifd in Meyer's ' Abbildtmyen 

 von A'ogel-Skeletten,' ])1. Oli. Tlie ,-kull of C. sinmttus is figured by Shufeldt 

 (Proc. V. S. Nat. Mus. 18S7. p. .386). 



