292 MR. W. p. PYCRAFT ON THE [Apr. 15, 



of the Accipitres is wanting save in the Falconidte, wherein 

 it is conspicuous. It differs, however, from that of the Striges 

 (1) in that the coronoid extends forwards along its whole 

 length, and (2) in that there is a small foramen lying immedi- 

 ately behind and above the vacuity for the passage of the 

 mandibular branch of the trigeminal. Furthermore, the external 

 latei-al border of the articulai-e develops a strong upward and 

 backwardly directed hook-like process forming a deep notch 

 between itself and the extreme postero-lateiul angle of the jaw. 



In the Striges, the BubonidiB have the coronoid terminating in 

 a spike-like fashion near the middle of the lateral mandibular 

 vacuity. In the Strigidje the vacuity is much smaller ; and the 

 coronoid terminates in fi'ont of it, in a truncated and spatulate 

 process. The V-shaped angle of the jaw is similar to that of the 

 Accipiti'es ; but the internal angular pi-ocess is relatively more 

 feeble, and the inferior border of the jaw is sinuous, whilst in the 

 Accipitres it is nearly straight. 



The Hyoid. 



The basihyal is partly ossified ; short ceratohyals are also 

 represented. The basibranchial has a diamond-shaped body 

 continu.ed backwards into a long style, representing the 2nd 

 basibranchial (urohyal). The cei'atobranchials are long. The 

 epibi-anchials are more than half as long as the ceratobranchials. 



iii. The Vertebral Column. 



All the pi'esyrisacral vertebra are heterocoelous. In all, save 

 the Falconidfe and Polyboridas, the thoracic vertebne ai'e free. 

 In the two families just mentioned all the thoracic A-ei'tebra3 are 

 ankylosed save the penultimate, which is free. Herpetotheres is 

 the only exception to this i-ule, having all the thoracics free. 



The cervical vertebrfe are relatively thick and short, and have 

 in the larger forms a somewhat swollen and massive appeai-ance. 

 The ankylosed cervical ribs, which ai'e present in all but the 

 atlas and axis, nevei- extend backwards as far as the end of 

 the centrum. The anterior lateral border of each is produced 

 upwards into a flattened plate, forming the outer wall of the 

 vertebrarterial canal. This pleurapophysial lamella is short 

 antero-posteriorly, its posterior border never extending as far 

 backwards as the middle of the centium. The dorsal border of 

 this lamella never unites with the centrum to enclose a fenestra 

 opening immediately behind the posterior zygapophyses, as in 

 Cariama for instance. ISTeural spines take the form of low median 

 tubercles : in the smaller forms these are but feebly developed. 

 In the 2nd to 4th vertebrfe the neui'al spines are moderately long 

 and columnar, especially in the Falcons ; the posterior angles of 

 the 2nd and 3rd turn upwards into blunt tubercular hyper- 

 apophyses. In Pandion the neural spines are obsolete, but the 



