50 E. Billings on the Genus Athyris. 
rocks, and might be thought superfluous. But the question is 
somewhat complicate and cannot well be decided, unless in 
view of all the RES Besides this, it is one upon which 
ny good naturalist is perfectly competent to give an opinion, 
although specially engaged in other departments. Few of these — 
have access to works on paleozoic fossils, and therefore for the — 
convenience of such as may feel inclined to spvoptigate the sub- 
ject, it is desirable to bring all the facts togather : 
ere is no dispute about the extent of the genera, and there- 
fore, the details of the internal characters need not be given. — 
It is purely a question of Natural-History Ethics, if I may be — 
permitted to use such a term. 
1. History Paty extent of the original Genus.—The original de- — 
scription was ea in the “ Synopsis of the Carboniteiun na 
ee Se Ireland” in 1844. From this work I shall make some _ 
ts, and shall miele along with the original figure two 
pais to further illustrate the subject. 
Figs eer 
Fig. 1—Copy of the original figure given by eget (without a specific name) to 
—— cafe acs of _ general form of an is. 
ca von Buc Th fin copied from Davidson’s Mono- 
sin of th the Britch Devon nian Br rachiopoda, III, fig. 18, Pal. Soc. fur 1862. 
The rent t-hand side is, in this copy, a little sire and the aperture in the 
sie than it is in the original figu 
Fig. : 8 Atharis ba da Dalman. Copied from Bavidast’s “ General Introduction,” 
Pp 
ae following extracts are from McCoy’s work above refer- 
“The 1 Shi Delthyride appears to be divided into the five following 
genera: 1. Spirifera era Sow. * eousposed of those onda the ath 3 spe- 
2. nia MeCoy, or the smooth ie in which the hinge-line is 
less sha the width of the shell, an a 
3. Athyris ee in tbe me =~ 
= yea: or 
