XXXVI 



to project the series formed by the representatives thereof till it is ex- 

 hausted, and then recommences with the next. 



In like manner, may we take, as the quasi-eldest, the form most like (in 

 essential features) the most generalized type, and continue the series till it 

 is exhausted. 



Applying the hint to the problem under consideration, we may take the 

 Crossopterygian as the most nearly related to the Dipnoan, and the repre- 

 sentative of the quasi-eldest branch, and continue the series by the succes- 

 sive juxtaposition of the forms next most allied till the pisciform series is 

 exhausted. Then may we resume the broken thread, and recommence from 

 the same ancestral stock with the quasi-younger branch, the Batrachian, 

 and treat it in the same manner. In this way, the natural sequence of 

 types would be preserved, and the least confusion engendered. 



And almost all the doubt and obscurity that reign over such questions 

 result from the confusion between the terms high and low with generalized 

 and specialized. 



Inasmuch, for example, as the Dipnoan is (1) the most generalized, and 

 therefore (2) more nearly related to the Batrachian than the typical fishes, 

 because (1) of that nearer affinity, and (2) the recognition of the quadru- 

 ped type as "highest," it is called "higher" than the fishes. 



Perhaps there are no words in science that have been productive of more 

 mischief and more retarded the progress of biological taxonomy than those 

 words, pregnant with confusion, High and Low, and it were to be wished 

 that they might be erased from scientific terminology. They deceive the 

 person to whom they are addressed ; they insensibly mislead the one who 

 uses them. Psychological prejudices and fancies are so inextricably associated 

 with the words that the use of them is provocative of such ideas. The 

 words generalized and specialized, having become almost limited to the 

 expression of the ideas which the scientific biologist wishes to unfold by 

 the other words, can with great gain be employed in their stead. 



TELEOST SEKIES. 



TELOCEPHALI. 



Among the most generalized of the typical fishes, and which have been 

 by common consent regarded as most nearly allied to the Ganoids, are the 

 physostomous Teleocephals, best known under the forms of the Cypri- 

 nids, Clupeids, and Salmonids. "With these, the Pikes, Scomberesocids, and 

 Perches, and, in fact, all those forms most familiar to men at large, nume- 

 rous as they are, appear to agree in all material respects as to skeletal 

 peculiarities and the character of the brain. With the reservations already 



