300 REPORT ON THE STATE CABINET. 



" Several of the above species do not ))elong to the group. This list shows 

 that D'Oebigny regarded the genus as including not only the types of Athyeis 

 and Spieigera, but also that of the Genus Merista (M herculea), Avhichlshall 

 notice further on. I think it quite certain that had D'Oebigny been aware that 

 the genus was capable of subdivision, he would have retained Athyeis for one 

 of the groups which have the beak imp erf ornate. Indeed, according to the laws 

 of nomenclature, he could not have done otherwise with any probability of 

 producing a permanent classification." 



I can agree entirely with Mr. Billings, that had D'Oebigny known of 

 any group of these fossils with imperforate beaks, he might have retained 

 for it the name Athyeis ; or had he known all that has since been learned, 

 he would have made some modification in his generic terms. 



On the sixth page of his article, Mr. B. cites M'Cot's re-descriptions 

 of the Genus Athyeis in 1852, when, for the first time, he placed A. tumida 

 under it ; forgetting, however, to allude to the fact already stated, that 

 M'Coy there cites Spieigeea as a synonym of Athyris. According to the 

 reasoning of Mr. Billings, and to reach the object he desires, we are to 

 wait, from 1844 to 1852, for Prof. M'Coy to complete his generic descrip- 

 tion of Athyris, and place under it a typical species of the genus. Suppose, 

 in the meantime, some one had based a Genus Billingsia on the Tere- 

 hratula tumida^ would the original description of M'Coy have covered 

 that too 1 



I will quote here the following paragraph of Mr. Billings, from page 54 

 of the American Journal of Science : 



" In the work cited, and in the third fasciculus, we find the following species : 

 ,.4. tumida, 8* concenlrica, ambigua, deroissyi^ expansa, globistriafa, globularis, 

 gregaria, paradoxa, peclinifera 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 M'Coy cited this as an Athyeis, no more renders it an Athyris 

 than it was made Ateypa by being thus described by Dalman ; and it was just 



* "S. concentrica" etc. Does Mr. Billings mean to say, or does he mean to be understood 

 that he is citing M'Cot, and that this author used the S. signifying Spirigera before the species 

 concentrica. We can only hope that it is a misprint of the jimerican Journal of Science. In 

 the British Palceozoic F'ossils, page 106, the Genus Athtkis is re-described, and ji. tumida placed 

 under it as a Lower Pateozoic species. On page 378 we have, under Devonian Mollusca, the Genus 

 Athyris repeated (with a reference to page 196 where the genus is described), and the species 

 ^. concentrica placed under it. Again we have the same thing repeated on page 432, where the 

 carboniferous species are introduced. As if to leave no farther doubt upon the subject, Prof. 

 M'CoT adds a note at the bottom of page 432, referring 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 observation 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." 



