466 PROF. HUXLEY ON THE CLASSIFICATION OF BIRDS. [Apr. 11, 



The sternum is not notched, but may present two foramina pos- 

 teriorly. 



The clavicles are relatively weak, and may be disunited, or absent. 

 When present, they are concave forwards as well as inwards. 



The tarso-metatarsus is very short in relation to the tibia, broad, 

 and flattened from before backwards. Its outer distal articular 

 head is divided by a groove into two articular facets. 



The fourth toe, articulated with this double facet, is permanently 

 turned backwards. The basal phalanges of the second, third, and 

 fourth digits of the foot are shorter than the penultimate. 



The inferior larynx has three pairs of muscles, and is, in other 

 respects, peculiar. 



The contour-feathers have a large aftershaft, and the oil-gland 

 when present has a circlet. 



The Parrots constitute one of the best-defined groups of birds, 

 having affinities, though of no very close character, with the Aeto- 

 morphse and the Coccygomorphse. 



-f 7. The COCCYGOMORPH^. 



The rostrum presents very various forms, and may be moveably 

 articulated with the skull. Basipterygoid processes are present only 

 in one genus (Trogon). 



The maxillo-palatines are usually more or less spongy. The pala- 

 tines are not developed into vertical plates, but are, as usual, hori- 

 zontally flattened. 



The distal end of the quadrate bone has the ordinary form. 



The sternum usually presents two notches on each side, and has 

 no bifurcated manubrial process (ex. Merops). 



The clavicles are convex forwards, and without any process deve- 

 loped backwards from the summit of their symphysis. 



The tarso-metatarsus is never remarkably elongated. 



It does not appear that anything can be predicated in common of 

 the pterylosis or of the characters of the oil-gland in this group. 



The larynx has not more than one, or at most two, pair of intrinsic 

 muscles. 



The Coccygomorphse are readily divisible into four groups by the 

 characters of their feet, as follows : — 



a. Thejirst toe turned forwards, as well as the others. 

 Coliidce. 



b. The fourth toe temporarily, or permanently, turned backwards, 

 as well as the first. 



Musojihayidce. Rhamphastidce. 



Cuculidce. CapitonidcB. 



Bucconidce. Galbulidce. 



