1871.] 177 [Wilder. 



and "nodi," yet for morphological purposes, we may indicate their 

 nature as subdivisions of primary segments by calling them "pseudo- 

 internodia" and "pseudo-nodi." 1 



III. NOMENCLATURE OF IDEAS. 



During the early part of the present century all kinds and degrees 

 of relationship between organisms and parts of organisms, were ex- 

 pressed by the single term Analogy, or by phrases which were even 

 more indefinite ; Swainson used the expression "immediate and re- 

 mote analogy," 2 but the distinction between these two relations was 

 not at that time fully recognized even by the authors who have since 

 done so much toward making it clear; 3 since 1846, however, these re- 

 lationships have been generally admitted to be of two kinds, homology, 

 or affinity, or internal or structural resemblance and analogy or external 

 or functional resemblance. * 



These two kinds of organic relationship have seemed to be the re- 

 sult of the operation of laws or principles, which, whether regarded 

 as of material or divine origin, may be not irreverently called the two 

 great commandments of Nature ; the first is variously termed, the 

 principle of adherence to plan, type, pattern, or idea', the second is called 

 adaptation to ends, to special uses, to final causes, etc, and by degrees 

 the second has come to be included under the single term Teleology ; 

 the first under the less appropriate term Morphology; so that, speak- 

 ing in the most general way, organisms which are morphologically or, 

 for short, morphically similar, are homologous, and those which are 

 teleologically or telically similar, are analogous. 



But it is evident that each of these general terms includes several 

 special kinds and degrees of relationship, and that these cannot all be 

 equally manifested in the same organs, or attributes of organs; we 

 should therefore endeavor to ascertain the respective criteria by which 

 these degrees of relationship may be recognized. In short there re- 

 mains to be done for Comparative Anatomy the kind of work which 

 Agassiz has begun for Zoology; and we must aim to discover the 

 morphic or taxonomic values of organs and systems of organs, 



1 A distinction between morphological and teleological joints was proposed by 

 me in 45, 28, with respect to the radio-ulnar articulation ; and this has been accepted 

 by Coues, 70, 370. 



2 Cuvier ; Anat. Comp. ; t. vn, p. 164. 



s Agassiz; Proc. Zool. Soc, 1834, p. 120; Owen; P. 1, 8. 1830, p. 28; 1838, pp. 12, 

 109, 145, 146; 1842, pp. 36, note, and 143. 

 * Strickland, 343, Owen, 20, Agassiz, 325. 



PROCEEDINGS B. 8. N. H.— VOL. XIT. 12 FBBBUAKY, 1872. 



