NO. II CLASSIFICATION, BIRDS OF THE WORLD — WETMORE 19 



Passeres. Affinity with the Bombycillidae may be queried, as the fossil 

 differs from Bomby cilia in the proportions found in the hind limb, 

 where both metatarsus and femur are longer in comparison with the 

 tibiotarsus, and the toes appear longer, as well as of different propor- 

 tion. The corvid affiliation also seems uncertain because of the slender 

 form of Palaeoscinis, since the skeleton of the crows and their relatives 

 is strong and robust. 



Separation of the two genera of leafbirds, Aegithina and Chloropsis, 

 in a family distinct from the Pycnonotidae is justified on the basis of 

 characters found in the skull. The entire palatal structure is slighter 

 than in Pycnonotus and allied genera, with the central plate of the 

 palatine reduced in area, and the transpalatine produced posteriorly. 

 The sphenoidal rostrum is slender, as is the orbital process of the 

 quadrate. In Pycnonotus the palatine is broad, the transpalatine proc- 

 ess distally is only slightly angular without posterior projection, and 

 both the rostrum and the orbital process of the quadrate are strong 

 and heavy. Herbert Deignan informs me that the group, recognized 

 by several authors, seems to have been first separated by Cabanis 

 (1847, p. 326), who designated it as the subfamily "Phyllornithinae" 

 based on Phyllornis Temminck, 1829. This generic term is antedated 

 by Chloropsis Jardine and Selby, 1826, so the family name based on 

 this genus will be Chloropseidae, rather than Aegithinidae which dates 

 from G. R. Gray in 1869 (P- 3 12 )- 



The fairy bluebirds, genus Irena, often have been placed with the 

 leafbirds but have no close connection with that group. The main 

 external peculiarity of Irena is found in the smooth, enamel-like tip- 

 ping found in adult males on the feathers of the central dorsal area 

 from the center of the crown back over hindneck, back, rump, and 

 upper tail coverts, and on the elongated under tail coverts. As this 

 is a secondary sexual character, not present in females, it has no value 

 at the family level. In the osteology, the skull differs from Chloropsis 

 and Aegithina in the completely open external narial opening, the 

 ossification of the vertical plate between the nares, the more inflated 

 lachrymal, and the more elongate maxillo-palatines. In the sternum 

 the depth of the notch on either side of the posterior margin relatively 

 is decidedly less, and in the pelvis the antitrochanter has the dorsal 

 margin much produced laterally. The general resemblance in these 

 matters is to species of the genus Oriolus. It may be observed further 

 that the feathers of breast and back in the aberrant species Oriolus 

 traillii and O. mellianus have smooth exposed ends that suggest the 

 condition found in male Irena. In view of these resemblances, and in 

 lack of important differences, it seems sufficient to include the fairy 



