BETWEEN TTPICAL BEPTILES AND OTIfER ANIMALS. 195 



noid having articular facets for the pterygoid bones, as in Lizards, 

 and in the similar prolongation of the presphenoid bone forward. 

 The pterygoid bones, as well as the palatines, are similarly divided 

 from each other mesially ; in birds, however, they are toothless 

 and small, and have attachments only with the quadrate, pala- 

 tine, and presphenoid. The quadrate bone is free in Serpents, 

 but of more typically lacertian than avian form ; and in Birds 

 the squamosal bone enters into the wail of the brain-case, while 

 in Serpents it has not even osseous union with the brain-case, 

 though more closely applied to it than is the case with the bone 

 in Lizards. 



There appear to be no Crocodilian characters beyond those 

 enumerated already, p. 174. 



The Chelonian characters are chiefly those mentioned on p. 184. 



The Lizard-characters of the vertebral column and palate are 

 chiefly given on p. 192. 



The Ilrodelan characters are some points in the head, such as 

 the suppression of alisplieuoids and orbitosphenoid bones. 



I made the foregoing comparisons many years ago for my 

 own use as a basis for other researches, and now offer them as a 

 contribution in aid of a better understanding of the term osteo- 

 iogical affinity in the reptilian ordinal groups, in the hope that 

 they form a Catalogue JRaisonne of the more obvious osseous 

 resemblances and points of supposed affinity, to which compa- 

 rative anatomists, dealing with new animals or with questions of 

 genetic relation, may have need to refer. And if, by indicating 

 the marked broad resemblances between a few organic types, 

 naturalists should find their toil lightened when pondering the 

 causes of these similitudes and of the more familiar structural 

 differences with which they are coupled — by here seeing at a 

 glance animals in which the resemblances are found, — I venture 

 to suggest that perhaps a similar synthetic examination of the ' 

 animal kingdom may furnish data for a morphological demon- 

 stration of the method of organic evolution, and for that more 

 definite knowledge of the nature of the relations between one 

 group of animals and another which the classifications of the 

 future will aspire to express. 



LINN, JOUEN. — ZOOLOGY. TOL. XII. 14 



