
262 THE AMERICAN NATURALIST. (VoL. XXXVI. 
different animals under every variety of form and function ”; 
homogeny (Lankester, '70) : * Structures which are genetically 
related, in so far as they have a single representative in a com- 
mon. ancestor, may be called homogenous.” E. B. Wilson 
(95, pp. 101-124) has shown that the comparative anatomical 
test of homology is more reliable than the embryological. 
Gegenbaur ('98, pp. 23—25) has given a full presentation of the 
distinctions as the basis of comparative anatomy ; in his recent 
great work ('98, p. 23) he presents the matter in terms which 
may be briefly analyzed with the usages of other authors, as 
follows : 
I. HOMOLOGY, GENERAL: as of vertebrze and limbs. 
I. HOMOTYPY: as of opposite limbs, eyes, kidneys, etc.’ 
?. HOMODYNAMY: (in part the “general,” in part the “serial,” 
homology of Owen; the ‘meristic” homology of Bateson). 
Corresponding limbs, parts, segments (e.g. the humerus and 
femur) on the same side of the body. 
3. HOMONOMY: parts which are in the same transverse axis of the 
; y, or on only one section of the longitudinal axis; ez., 
the rays of the fins of fishes, the single fingers and toes of 
the higher vertebrates are homonomous organs. 
- 
— 
. HowoLocy, SPECIAL: (the “« homogeny " of Lankester). 
1. COMPLETE HOMOLOGY of elements which have retained their rela- 
tions unchanged, as of single bones from the Amphibia to the 
Mammalia. : 
2. INCOMPLETE HOMOLOGY, as of organs which have either gained 
new parts or lost certain of their parts. 
4. defective, as in comparison of fins of teleosts and of selachians. 
b. augmentative, as in the heart of cyclostomes and of the higher 
^ vertebrates. VEM ; 
c. imitative, as where different vertebræ connect with the ilium 
and become sacral. ` 
Hi ‘Homomorpny (Fürbringer): from these homologies certain structures 
are to istinguished as homomorphic which are more or less 
similar to each other but stand in no phylogenetic connection.! 
_Homomorphy comes nearest, as we understand it, to the “ homo- 
v»: Pplasy” of Lankester, but the latter term has the priority of 
£t 
* ^3 Literally translated from Gegeabagn 0. 
