262 TWENTIETH REPORT ON THE STATE CABINET. 



" In the work cited and in the 3d fasciculus, we find the following species : — A. 

 tumida, S* concentrica. avihigua, deroissyi, expansa, globistriata, globularis, gregaria, 

 paradoxa, pedinifera, and squamigera. This shows clearly enough his views of the 

 genus; that is to say, that as it was then understood, it included both A. tumida and 

 A. concentrica. In commenting on this, Prof. Hall says : — ' The fact that McCoy 

 cited this as an Athyris, no more renders it an Athyris than it was made Atrypa by 

 being thus described by Dalman; and it was just as free for the foundation of a 

 genus after the citation of McCoy as before.' This is true enough in part. It was 

 free for the foundation of a genus until 1853, when Davidson used it for that pur- 

 pose; but since 1853, it has never been free." 



This statement that Mr. Davidson used A. tumida for the foundation 

 of a genus, may be " unsophisticated " enough to serve the writer's purpose ; 

 but it seems to us that a little explanation maybe necessary. Mr. David- 

 son, in a spirit of conciliation, proposed to retain Spirigera for A. 

 concentrica and similar forms, and to restrict the term Athyris to such 

 forms as A. tumida, A herculea, etc. ; but the remonstrances of naturalists 

 aofainst the violation of an established rule induced him to abandon 

 Spirigera and adopt Athyris, citing tbe former as a synonym.! Mr. D. 

 never used the A. tuinida as the foundation of a genus in any other sense ; 

 and he himself abandoned the attempted compromise, and subsequently 

 placed A. tumida with A. herculea under the genus Merista of Suess, and 

 this was where I found it when I began my investigations upon the species. 

 Does this appear like using it for the foundation of a genus ? Had 

 tbe A. tumida proved, as it was supposed to be, congeneric with A. 

 herculea (a Merista), would it still have been the type of Athyris ? Cer- 

 tainly so according to Mr. Billings' reasoning; and I might ask of him, 

 whether he knows its internal structure sufficiently to assert anything regard- 

 ing its true generic place and relations beyond the fact that externally it is 

 similar to Merista, and possesses internal spires ? But whether these spires 

 are similar to A. concentrica or to Meristella as illustrated by the writer, 

 remains yet to be proved. 



It is perhaps not worth while to follow in detail the arguments of Mr. 

 Billings. The rules of nomenclature, cited by him, seem to be opposed 

 to his arguments, particularly the following : — "4. A generic name should 

 " always be retained for that portion of the original genus which was con- 



* *' )S. concentrica,^^ etc. Does Mr. Billings mean to say, or does he mean to be under- 

 stood that he is citing M'Coy, and that this author used the S. signifying Spirigera 

 before the species concentrica. We can only hope that it is a misprint of the American 

 Journal of Science. In the British Palasozoic Fossils, page 196, the Genus Athyris is 

 redescribed, and A. tumida placed under it as a Lower Palseozoic species. On page 378 we 

 have,' under Devonian MoUusca, the Genus Athyris repeated (with a reference to page 

 196, where the genus is described), and the species A. concentrica placed under it. Again 

 we have the same thing repeated on page 432, where the carboniferous species are intro- 

 duced. As if to leave no farther doubt upon the subject, Prof. M'Coy adds a not* at the 

 bottom of page 482, refering to page 196, as follows : 



^'I see that by some accident, in the character given at the above page [196], this 

 ^' genus is stated to be without foramen, from my old diagnosis, which escaped obser- 

 ** vation in correcting the proofs. I formerly supposed with Prof. Phillips, that the 

 '* minute opening at the apex of the beak of the receiving valve was caused by 

 *' fracture ; continued observations have, however, since shown me that it is a natural 

 *' character of the genus as the Continental authors contended." 



t See note on pages 264 and 265. 



