524 TRANSACTIONS OF SECTION D. 
observed by experiment on other rudimentary organs (lens-formation, bone- 
development). I have called it ‘imitation,’ and I regard it as of fundamental 
importance in relation to theories of homology. 
4, Discussion on Convergence in the Mammalia. 
(i) Opening Remarks by Dr. H. Gapow. 
(ii) Un nouveau cas de Convergence chez les Mammiféres: Balena et 
Neobalena. Par le Professeur Louis Dotuo, Sc.D., C.M.Z.S. 
Contrairement aux opinions regues, Neobalena n’est pas une vraie Baleine. 
Elle n’est pas, non plus, intermédiaire entre les Baleines et les Balénoptéres. 
Mais c’est une véritable Balénoptére, simplement adaptée 4 la maniére de 
vivre des Baleines. 
Done, un nouveau cas de Convergence, chez les Mammiféres. 
Les preuves 4 l’appui de cette assertion paraitront dans les Proceedings de 
la Société Zoologique de Londres pour 1913. 
(il) Convergence in Mammals. By Professor Van BEMMELEN. 
Convergence is generally understood to mean the similarity between organisms 
not nearly related to each other—for instance, Cetacea and fishes, bats and birds, 
and soon. But there may—or, rather, there must—exist a far greater similarity, 
based on convergence, between near relatives. And it must be exceedingly difti- 
cult to distinguish this kind of convergence from the homologies caused by 
heredity ; that is to say, by the influence of a common ancestor. 
Yet it is clear that when,:under equal influences of the environment and 
similar exigencies of the struggle for existence, organisms very different in 
original build are enabled to develop one and the same kind of new adaptations, 
the same must be the case in a far higher degree when nearly related organisms 
are subjected to those identical circumstances. To cite an example : our European 
mole is related to the shrew; the golden mole of the Cape, on the contrary, is a 
specialised offspring of the Centetidw. Both have adapted themselves in a 
similar way to the subterranean mode of life. Is it then not probable that 
different species of shrews at various points of the earth, influenced by those 
similar life-conditions, might have been changed into different species or at least 
races of moles? 
These possibilities must always be kept in view in all our speculations about 
evolution of new forms. Monophyletic origin, taken in its strictest sense, would 
always involve the highly improbable hypothesis of one single pair of individuals 
as the ancestors of each new species. As soon as we incline to the opposite 
opinion—the whole bulk of the individuals of a certain species all changing in the 
same way under the influence of changed external conditions of life into a new 
local race, variety, sub-species, and, finally, into a new species—we have 
admitted the existence of parallel evolution among near relatives. 
Therefore I am convinced that all studies on convergence must start with the 
careful comparative investigation of those nearest relatives. To cite an example: 
Some years ago I took up the question of the relationship between the hare and 
the rabbit. Is the first an offspring of the second, or vice versa, or have both 
derived from a common ancestral form, more generalised and more like the rest 
of the Duplicidentata (and also more like the Simplicidentata)? With many 
restrictions, I believe the second assumption to be the most probable; but what 
interests us here is the conclusion I arrived at in comparing not only the 
European hare to our rabbit, but more generally the different sub-genera of 
the genus Zepus to each other. I found myself obliged to assume that the 
adaptation of a free-living hare-like Duplicidentate to a fossorial subterranean 
mode of life had taken place several times in different parts of the world, and 
i, 
