STUDIES OF SOME EARLY SILURIC PELMATOZOA 



r.Y r.EORGE H. HUDSON 



In a somewhat caustic criticism of two papers by G. Ham- 

 bach/ the late Dr P. Herbert Carpenter - laid such emphasis 

 on the exhaustive study of the morphology of ^ the nearest living 

 representatives of any fossil form, for one who wishes to under- 

 stand the latter, as to convey the impression that such study is 

 the only legitimate means to the required end and that " certain 

 American paleontologists and more especially Mr G. Hambach " 

 (loc. cit. p. 277) are innocent of eating of the fruit of this tree 

 of knowledge. No student of the present day is likely to deny 

 the value of exhaustive study in the direction indicated, but in 

 work of this kind it must never be maintained that any one 

 avenue of approach is the only one that is proper or valuable. 

 When Doctor Carpenter says '' In order to understand, even 

 with an approximate degree of correctness, extinct groups, such 

 as the Blastids, Merostomata, Dinosauria, and others, a far more 

 extensive acquaintance with the recent members of the same 

 subkingdom is necessary, than for the interpretation of fossil 

 Brachiopoda, sponges, corals, Mollusca and fishes " (loc. cit. p. 

 2yy-y^) , he only emphasizes the fact that the fields in which he 

 insists that a still greater amount of study is needed are just 

 those fields where divergent development and remoteness of 

 relationship have most effectually masked the information sought. 

 The relationship between phyla of the animal kingdom is but 

 one degree more remote than that between such distinct classes 

 as Blastoidea and Holothuroidea and the advice to make " a far 

 more extensive acquaintance " with the morphology of the living 

 dibranchiate Cephalopoda before attempting the restoration of 

 a Brontosaurus would seem highly absurd. 



The study of the morphology of living forms is a very essential 

 factor in the establishment of true phylogenies. Even here, 

 however, living forms must receive study from broader and 



1 Contribution to the Anatomy of the Genus Pentremites, with Descrip- 

 tions of New Species. Trans. St Louis Acad. Sci. v. 4, no. i, 1881, p. 145- 

 60, pi. A and B. 



Notes about the Structure and Classification of the Pentremites. Trans. 

 St Louis Acad. Sci. v. 4, no. 3, 1884, p. 537-47. 



2 Further Remarks upon the Morphology of the Blastoidea. Ann. Mag. 

 Nat. Hist. April 1885, p. 277-300. 



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