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NEW YORK STATE MUSEUM 



scribed four species from the Beekmantown beds at Beekmantown. 

 These and the Fort Cassin fossils had been secured by Professors 

 Seely and Perkins, the untiring collectors of the fossils of the 

 Champlain basin. 



H. Schroder [1891] has had occasion to discuss the generic rela- 

 tions of some of the Fort Cassin cephalopods ; and Hyatt has used 

 the large collection of Fort Cassin fossils deposited in the National 

 Museum and his own collections to elaborate the phylogenetic rela- 

 tions of the greater number of the coiled forms [1894]. 



Hyatt has considerably increased the number of nautiliconic 

 species of the Nautiloidea from the Lower St Lawrence region and 

 Newfoundland, has laid open the lines of evolution of the Cepha- 

 lopoda by his penetrating investigations into their phytogeny, and 

 supplied a new system, which is here adopted. 



It may be stated here that this system so far as the nautiloid 

 cephalopods are concerned may be indeed, as we believe it is, a true 

 expression of the natural relationship of the forms and therefore be 

 considered as an important improvement on the former artificial 

 arrangement by the degree of curvature of the conch ; yet anyone 

 who seriously attempts to distribute a series of cephalopods of 

 average preservation in this system can not fail to observe that its 

 fundamental criteria of division, as the character of the funnels or 

 septal necks and the internal structure of the siphuncle are so diffi- 

 cult of observation and fail so frequently of preservation or are 

 so obscured that a positive decision as to the relation of the 

 specimens in hand to the larger divisions and thereafter to the 

 families is in a great number of cases impossible. And again 

 where these have been recognized, it becomes apparent that if the 

 principles of Hyatt's division are to be followed out, the number of 

 genera established, large as it is, is yet by no means sufficient ; and 

 that the generic diagnoses, often construed on theoretic grounds, 

 frequently do not occupy contiguous sections in the uninterrupted 

 phylogenetic series, thereby leaving wide gaps between the hitherto 

 denned genera. 



It is for these various reasons that such a considerable number of 

 the species here described are considered as not yet conclusively deter- 

 mined genetically. In several cases, rather than create new genera, 

 we have placed the species with the nearest genus, leaving the task 

 of filling the gaps in the generic series to him who will undertake 

 the work — as difficult as it is meritorious — of continuing the in- 

 vestigation where Hyatt unfortunately had to leave it. 



