ELEMENTARY SKETCH OF THE OSTEOLOGY OF BIRDS. 13 



the inner ends of the same bones, leave a broader or narrower 

 fissure (whence the name of the group) between themselves 

 and the vomer, and do not unite either with it or with them- 

 selves. With the exception of the fowl, all Schizognathous 

 birds have small bones known as « meso-ptery golds," which 

 do not occur in mammals. , r xi. 



(III.) The group Desmognath^^ comprehends such or the 

 Cuvierianorders*Grallse {Ardeidcs, Giconida and Tantalida) , ^n^ 

 Natatores (Anatida, Pkcenicopterida and Pelicanida) as are not 

 Schizognathous, the Accipitres or Raptores, the Scansores (Pica- 

 rise in part), and a large number of the old fissirostral Passeres or 

 Insessores. This group includes such a heterogeneous mixture 

 of birds that its importance in classification may be open to 

 doubt, though morphologically it is of the highest interest. I 

 have selected as an illustration of this form of palate the skull 

 of the Common Heron, {Ardea cinerea) (pi. II, fig. 3). In 

 this group the vomer (vo.) is frequently very small, or may 

 be entirely absent ; when present, it is always slender and pointed 

 anteriorly. The maxillo-palatine processes (mxp.; are united 

 across the middle line (whence the name of the group) either 

 directly or by the intermediate ossifications of the nasal septum. 

 The ends of the palatines (pi.) and the anterior ends of the 

 pterygoids articulate directly with the sphenoidal rostrum ; and 

 the basi-pterygoid processes are placed on this rostrum. 



(IV.) The remaining Carinatse are comprehended in the 

 group ' iEgithognathsef in which the palatine structure is in 

 some resp'ects "intermediate between that of the Schizo-and 

 Desmognathous groups ; while in others it is peculiar. A skull 

 of a raven, (Corvus coraa;) (pi. II., fig. 4) is given as an example 

 of this form of palate. 



The vomer (vo.) is a relatively broad bone, abruptly truncated 

 anteriorly and deeply cleft behind, and which embraces the 

 sphenoidal rostrum. The maxillo-palatine processes are slender 

 at their origin, and extend obliquely inwards and backwards over 

 the palatines (pi.), ending beneath the vomer in expanded 

 extremities, which do not become united by bone, either with one 

 another or with the vomer. 



The birds comprized in these three last groups have been again 

 sub-divided into families from the characters afforded by the bones 

 of the palate. It is not, however, within the scope of this slight 

 sketch to indicate these minor divisions, and the student, who 

 desires to go further into this subject, is accordingly referred to 

 the papers of Professors Huxley and Parker on this subject. 

 It may, however, be noted here that Mr. Garrod has div ided the 



* From 2E0-/X0S a bond, and yvnQo<s. 



t From atyt^os, a sparrow, and yvaQof, jaw. 



