REFERENCES AND QUOTATIONS. 327 
any scientific discussion, on finding that the pedigree of the Verte- 
brata, and therewith of man, is actually traced beyond the verte- 
brated animals to so low a being as the Ascidians. It is otherwise 
with the critics of Kowalewsky’s and Kupffer’s observations, who 
acknowledge the facts, but think themselves obliged to differ in 
their interpretation. One of these is A. Giard, in his work on 
the “ Embryogénie des Ascidiens.” (Archive de Zoologie expéri- 
mentale, Paris, 1872.). The pupil of Lacaze Duthiers. says :—“ La 
chorde et Tappendice caudale sont chez la Jarve Ascidienne des 
organes de locomotion d’un importance assez secondaire malgré 
leur, généralité, dour gu'on les vote disparattre presque entidrement 
dans le genre Molgula, ov ils sont devenus inutiles par suite des 
meeurs de animal adulte ; Phomologie entre cette chorde dorsale 
et celle des vertébrés n’est donc qu’une homologie d’adaptation 
déterminée 4 remplir Viodentité des fonctions, et n’indique pas de 
rapports de parente immediate entre les vertébrés et les Ascidiens.” 
The author thus denies the consanguinity of the vertebrate animals 
and Ascidians, and traces back to adaptation the resemblance 
approaching identity occurring in the organs of the two. The 
inferences in these few sentences appear to us utterly at fault. 
The circumstance that in Molgula, and many other Testacea, de- 
velopment takes a narrower course, makes as little alteration in the 
importance of the facts as, for instance, the Nauplius development 
of the Peneus observed by Fritz Miiller, or the Navicula of the 
Molluscs, is prejudiced by the fact that the other Decapods have 
forfeited the Nauplius phase, or the Landsnails the navicula phase. 
But it is simply incomprehensible in what the identity of functions 
is to consist which in the Vertebrata was capable of producing 
the notochord, with, it is particularly to be remarked, the spinal 
cord (which M. Giard entirely forgets); and, in the other case, 
the “homologie d’adaptation.” We, on the contrary, see these 
organs performing different functions, because in the one they 
remain of fundamental importance through life, and not in the 
other. Thus we conversely lay the stress on the morphological 
identity accompanying functional difference. M. Giard adduces 
no facts. 
*® T. H. Huxley, Manual of the Anatomy of the Vertebrated 
Animals. German Ed. 
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