Fauna of the Niagara and Upper Silurian Rochs. 119 



largely magnifying optical instruments, I have been unable with 

 the single exception of the seta filaments at the extremities of the 

 thoracic segments of Calymene — to discover any apppearance 

 having the slightest resemblance to the strong jointed legs ; char- 

 acteristic of the limulus group. 



Since preparing this society paper, I have received from Mr. 

 p^ C. D. W(^lcott, Curator State Museum Natural History, Albany, 

 N. Y., two pamphlets on the organism of the trilobite, entitled "a 

 preliminary notice of the discovery of the natatory and branchial 

 appendages of the trilobite," also an explanatory letter from the 

 author respecting the unoertanty of his discoveries, but hopeful 

 of a final satisfactory result. 



A copy of the twenty-eighth Eegents' New York Eeport by Prof. 

 Hall, with reference to plate 34, fig. 14, illustrating points of at- 

 tachment for supposed natatory organs, also fig. 13, which might 

 be a sub-section in conjunction with other parts of a folded speci- 

 men, could be readily construed into a semblance of strong 

 jointed legs, resembling the limuloid species. Mr. W^lcott's theo- 

 ries are formed from incised specimens of " casts of the exterior," 

 while my conclusions are the result of examinations made of "casts 

 of the interior." 



In our investigations, Mr. Wdlcott and myself ma}^ be in a 

 chameleon sense, right or wrong, as to the opinions we may 

 form, being largely influenced by the circumstances which govern 

 our actions in a similar manner — as several years ago — a diver- 

 sity of opinion existed between Professors Billings, Woodward, 

 Yerrill and Dana. ^. 



Permit me to simply state that I think I have conclusive evi- 

 dence, that " trijo bites did not swim on their bac ks," they did not 

 ha ve stout jointed legs, they did not rest with th eir dorsal surface 

 downwards, and they did not belong to the higher order of entro- 

 mostracans. But more extended and fully explanatory views 

 concerning the trilobite, will appear in a work I am now prepar- 

 ing for the press. 



But whatever the result may be of our persevering labors, nat- 

 ural science will no doubt be benefited by our efforts to solve 

 what have been so long problematical statements. 



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