1871.] 327 [Wilder. 



tion of the other kind of morphical relations, plural homologies, upon 

 which zoological classification is based; since, although few have 

 spoken of the two halves of a single individual as if they were two 

 distinct individuals and comparable in like manner, yet it is not 

 probable that any one will object to such a view of the case, and 

 such a method of comparison. 



May we then conclude that morphical value is essentially equiva- 

 lent to taxonomic or zoological or classificatory value, and that the 

 only difference is that the former is used when two parts of the same 

 individual are compared, while the latter is used when two different 

 individuals are compared, with a view to ascertain their zoological 

 relationship ; if so, then morphical value is value in respect to single 

 homologies, taxonomic value is value in respect to plural homologies ; 

 and since both are morphical relations, it seems probable that the 

 same attributes, organs, systems, species and stages of development 

 which have been found available in the one, should be given a like 

 absolute and relative importance in the other class of morphical 

 questions. 



This conclusion seems warranted by the language of high author- 

 ities, 1 who either use morphological as if equivalent to taxonomic 

 value, or imply that morphical relations, near and remote, are the 

 true test of zoological affinity. 



Assuming then provisionally, and until decided objection is raised 

 by others, that morphical value and taxonomic value are correlative, 

 we are now justified in considering the zoological criteria, which have 

 been admitted, in order to ascertain the relative morphical value of 

 the characters already mentioned ; but here, unfortunately, we meet 

 with a most unsatisfactory difference of opinion. 



For instance, we find the same high authority making two incom- 

 patible generalizations, as follows : " The generative organs, being, 

 those which are most remotely related to the habits and food of the 

 animal, I have always regarded as affording very clear indications of 

 its true affinities ; we are least likely in the modifications of these 

 organs, to mistake a merely adaptive for an essential character.'* 

 Owen (on the Dugong, Proc. Zool. Soc, vol. i, p. 40.) " Teeth are 

 always most intimately related to the food anc^ habits of the animal 

 and are therefore important guides in the classification of animals. ' ' 

 (63, 1, 361). 



lAgassiz (201, fere), Huxley (251, 2 and 100), Gill, American Naturalist, vol. iv, 

 Proc. Am. Ass. Adv. Soc, 1870, and Rolleston (294, xxii). 



