i 2 The Ganoids 



Ganoids. They all have, for example, (i) the paraglenal ele- 

 ments undivided (not disintegrated into hypercoracoid, hypo- 

 coracoid, and mesocoracoid ; (2) a humerus (simple or divided, 

 that is, differentiated into metapterygium and mesopterygium) ; 

 and (3) those with ossified skeletons agree in the greater number 

 of elements in the lower jaw. Therefore, until these coordi- 

 nates fail, it seems advisable to recognize the Ganoids as con- 

 stituents of a natural series; and especially on account of the 

 superior taxonomic value of modifications of the brain and 

 heart in other classes of vertebrates, for the same reason, and 

 to keep prominently before the mind the characters in question, 

 it appears also advisable to designate the series, until further 

 discovery, as a subclass. 



" But it is quite possible that among some of the generalized 

 Teleosts at least traces of some of the characters now consid- 

 ered to be peculiar to the Ganoids may be discovered. In 

 anticipation of such a possibility, the author had at first dis- 

 carded the subclass, recognizing the group only as one of 

 the ' superorders ' of the Teleostomes, but reconsideration 

 convinces him of the propriety of classification representing 

 known facts and legitimate inferences rather than too much 

 anticipation. 



"It is remembered that all characters are liable to fail with 

 increasing knowledge, and the distinctness of groups are but 

 little more than the expressions of our want of knowledge of 

 the intermediate forms; it may in truth be said that ability 

 to segregate a class into well-defined groups is in ratio to our 

 ignorance of all the terms." 



