76 GENERAL ORNITHOLOGY. 



any of which arc teleotypio of their ancestors. It may he further observed that any form 

 which is teleotypio in its own group, is prototypic of those derived from it. Thus, the 

 Archeeojiteryx, so prototypic of modern birds, was a very highly specialized teleotype of its 

 own ancestry. A little reflection will also make it clear that the same principle of antitypes 

 (opposed types) is applicable to any of our gmips in zoology. Any group is teleotypio of the 

 next greater group of tvhich it is a member; prototypic of the next lesser one. Any species is 

 teleotypio of its genus ; any genus, of its family ; any family, of its order ; and conversely ; 

 that is to say, any species represents one of the ulterior modifications of the plan of its genus. 

 The Class of Birds, for example, is one of the several tcleotypes of Vertehrata, i. e., of the 

 vertebi-ate plan of structure ; representing, as it does, one oi several ways in which the 

 vertebrate prototype is accomplished. Conversely, the Class of Birds is prototypical of its 

 several orders, representing the pjlan which these orders severally unfold in different ways. 

 And so on, throughout any series of animals, backwards and forwards in the process of their 

 evolution ; any given form being teleotypio of its predecessors, prototypic of its successors. 

 All existing forms are necessarily teleotypio, — only prototypic for the future. Prototype, in the 

 sense here conveyed, indicates what is often expressed by the word archetype. But the latter, 

 as I understand its use by Owen and others, signifies an ideal plan never actually realized; the 

 " archetype fif the vertebrate skeleton," for example, being sonietliing no vertebrate ever pos- 

 sessed, but a theoretical model — a generalization from all kno^m skeletons. The oon'espond- 

 ence of my use of "prototypic " with a comm(.]n employ of " arohetypic," and of "teleotypio " as 

 including both " attypic" and " etypic,'' is noted below.^ 



The actual and visible genetic relationships of living forms being practically restricted to 

 individuals of the same species, — parents and offspring "specifically" identical, — it would seem 

 at first sight that species must be the modified descendants of their respiective genera, in order 

 to be teleotypio of any such next higher group. But nothing descends from a genus, or any 

 other group; everything descends from individuals; a '' genus," like any other gTOUjj, is an 

 abstract statement of a relation, not a begetter of anythmg. To illustrate: the "genus 

 Tardus " is represented, let us say, by a score of species: if these species be rightly aUooated 

 in the genus, they are all the modified descendants of a form which was, before they severally 

 branched off, a specific form ; and the "genus Turdus" in the abstract is simply that form ; 

 and that form is prototypic of its derivatives. In the concrete, as represented by its teleotypes, 

 the genus Turdus sums the modifications which these have collectively undergone, M'ithout 

 specifying the particular raodifioatious of any of them ; it expresses the way in which they are 

 all like one another, and in which they are all unlike the representatives of any other genus. 

 Thus what is above advanced is seen to hold, though genera and all other groups are actual 

 descendants of individuals specifically identical. 



Generalized and Specialized Forms. — Taking any one group of animals — say the genus 

 Turdus, of numerous species — and considering it apart from any other group, we perceive that 

 it represents a certain assemblage of charactc^rs peculiar to itself, aside from those more funda- 

 meutal ones it includes of its family, order, etc. Its particular characters we call "generic." 

 Among the numerous teleotypio forms it includes, there is a wide range of specific variation, 



' " Arclu'lijpical cli.Trac'ter.s are those wliidi a group derires from its progenitor, and with wliicli it com- 

 iiiinces, but \yhicli in mucli modified descendants are lost; sucli, for e.vample, is tlie dental formula of the Educa- 

 hilia (M I PM :| C 1 1 ii X 2), —a formula, as shown by Owen, very prevalent among early members of tlie group, 

 Iiiit generally ileparted from more or less in those of the existing faunas. Afti/picat characters are those to the 

 acquisition of which, as a matter f>f fact, we find that forms, in their journey to .a specialized condition, tend . . . 

 Sti/pical characters are exceiitional ones, and which are exhibited by an eccentric offshoot from the common stock 

 of a group." — (Gt«, Pr. Am. Assoc. Adv. Sci., XX, 187.3, p. 29.3.) To illustrate in birds: A generalized lizard-like 

 type of sternum is arcludypic of any bird's sternum. The sternum of the lizard-like animals whence birds 

 actually descended is prototypic ; the keeled sternum of a earinate bird is nttyjncnl in most birds, ('typical in the 

 peculiar state in which it is found in Strinyops ; but equally teleotypio in both instances. 



