264 TWENTIETH REPORT ON THE STATE CABINET. 



outset. Referring to an article in the Canadian Journal, lie says : " In 

 " that paper I described two species with closed beaks, A. clara and A, 

 '•'■ maia, which no doubt belong to the genus. The others with perforated 

 " beaks I marked doubtful, thus : — A. (?) scitula (Hall) ; A. (?) dusia^ 

 " n. s.; A. (?) unisulcata (Conrad); A. (?) rostrata (Hall); A. (?) 

 chloe^ n. s." 



The paragraph following this does not seem to be relevant to the sub- 

 ject ; and the remarks about Mr. Hall having proposed a Genus Meristella 

 have been so often before the public in some form, that it is scarcely worth 

 while to occupy space by citing what is said in this place. I may, however, 

 briefly allude to a former statement of Mr. Billings, in the Canadian 

 Journal, (1860), that I had proposed the name Meristella for those "shells 

 " which have Athyris tumida for the type." This is quite incorrect, so far 

 as I am aware. The generic name was proposed in I860, and used by me 

 in the descriptions of the plates of Vol. iii, Tal. N. Y.; and under the 

 generic description, published in 1861, I gave as examples M. Icevis, M. 

 hella and M. arcuata of the Lower Helderberg gTOup, besides others. I 

 cited M. tumida as belonging to the genus, simply from a general similarity 

 of external form, and similarity of muscular impression in the ventral 

 valve. Of " the others with perforated beaks," etc , cited above, the A.{V) 

 scitula has no more a perforated beak than has A. tumida. Nor does Mr. 

 Billings mention this fact in his original notice of the species in the 

 Canadian Journal ; and in the original description of A' (?) clusia, Mr. 

 Billings says : "beak of ventral valve erect, apparently a little incurved 

 at the tip." Of A. (?) unisulcata^ Mr. B. says "the beak is incurved over 

 the umbo of the dorsal valve, but its tip not quite in contact^with the 

 umbo of the dorsal shell." The figures of this species by Mr. Billings 

 do not show a perforation in the ventral beak, nor is it more conspicuously 

 perforate than A. tumida. The A. {f) rostrata has a perforation, and is a 

 Terebratula. a. (?) cJiloe has a perforation in the apex, and belongs to 

 the Genus TreMatospira = T. hirsuta (Hall), having since been placed 

 under Ketzia by Mr. Billings. Mr. B. afterwards proposed a genus 

 Charionella, under which he has placed the " ^. (?) scitula^ A. (?) 

 rostrata,''^ and others ; giving, as I have said before, an impossible hinge- 

 structure. 



We will merely give a moment to the two species which Mr. B. says " no 

 doubt belong to the genus" Athyris quoted above. A. clara is the Atrypa 

 nasuta of Conrad, of which I have specimens from New-York and Canada; 

 and typical forms, from the original locality cited by Conrad, are figured 

 in Vol. iv of the Palaeontology of New-York. The beak of the ventral 

 valve is often apparently imperforate, from being closely incurved 

 upon the other valve; but it is not imperforate in fact. If it be any 

 satisfaction to Mr. Billings to know the fact, I may mention that a critical 

 examination of the internal spires of this species has shown it to be somewhat 

 different from the similar appendages of typical forms of Meristella ; but 



