BETWEEN TYPICAL REPTILES AND OTn.EK ANIMALS. 195 



noid Having articular facets for tlie pterygoid bones, as in Lizards, 

 and in the similar prolongation of tlie prespbenoid 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, palatine, 

 and presphenoid. The quadrate bone is free in Serpents, but of 

 of more typically lacertian than avian form ; and in birds the 

 squamosal bone enters into the wall 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 enu- 

 merated 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. lf)2. 



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

 the suppression of alisphenoids and orbitosphenoid bones. 



I made the foregoing comparisons many years ago for my own 

 use as a basis for other researches, and now ofier them as a con- 

 tribution in aid of a better understanding of the term osteological 

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

 form a Catalogue Raisonne of the more obvious osseous resem- 

 blances and points of supposed affinity, to which comparative ana- 

 tomists, dealing with new animals or with questions of genetic rela- 

 tion, 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 difierences 

 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 demonstration 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, VOL. XII. 14 



