28 ELEMENTARY SKETCH OF THE OSTEOLOGY OF BIRDS. 



{Sauro]nath(B.) 



26. Celeomorphce (Woodpeckers and Wrynecks.) 



/8. Maxillo-palatines united, either by coalescence with 

 nasal septum, or by meeting in a suture in 

 middle line, or by complete anchylosis of plates 

 of both sides. 



27. Aetomorphae (Birds of Prey.) 



28. PsittacomorphcB (Parrots.) 



29. Coccycomor'phcd (Cuckoos, Kingfishers, Trogons, 



Bee-Eaters, Hornbills, and Hoopoes.) 



30. ChenomorphcB (Anserine Birds.) 



31. AmphimorphcB ^Flamingoes.) 



32. PelargomorphcB (Storks and Herons.) 



33. DysporomorpJice (Cormorants.) 



F,S. — Since the above has been in type, I have seen two 

 very important papers by Professor 0. C. Marsh,* in which an 

 entirely new interpretation of the homology of part of the 

 avian pelvis is put forth. On page 23 of this sketch, I have 

 called the long slender bone forming the lower border of the 

 avian pelvis, the pubis (plate III, fig. 5, pb.) Professor Marsh, 

 from the study of the pelvis of some new American Dino- 

 saurian reptiles has, however, conclusively proved that this 

 slender bone is not the homologue of the pubis of a crocodile, 

 (which is a stout bone, placed in front instead of behind the 

 acetabulum), but is the homologue of a similarly-situated 

 process of the pelvis of certain Dinosauris. In those animals 

 the pubis consists of a stout portion in front of the acetabulum, 

 which is directed downwards and forwards, and which corre- 

 sponds to the pubis of the Crocodile, and of a second slender 

 portion, behind the acetabulum, which runs parallel to the 

 ischium, and which corresponds to the so-called pubis of the 

 bird. This slender portion ossifies separately, and has been 

 named by Professor Marsh the posi-pubis. The homologue of 

 the reptilian pubis proper is represented in the pelvis of the 

 bird by the small process which occurs on the lower border 

 immediately in front of the acetabulum. This small process 

 is most developed in those birds which use the hind limb to a 

 creater extent than is usually the ease ( Geococcyx, Dromceus, 

 Apteryx.) The slender post-pubis seems to be developed only 

 in birds, and in those Dinosaurian reptiles, which seem in 

 walking to have habitually used their hind limbs only. The 

 Dinosaur is, however, distinguished from the bird by always 



* American Journal of Sciencej Noremlier 1878— January 1879. 



