34 
PROCEEDINGS OE SOCIETIES. 
knowledge, yet that our knowledge of the habits and structure of any 
fossil, however perfect, is at best extremely small, compared with our 
acquaintance with living forms. It is not, therefore) necessary to be 
so precise in our subdivisions of fossil as of recent genera, and no greater 
injury can be done to the science of Geology than has been, by the use¬ 
less multiplication of worthless names, founded on distinctions which are 
necessarily trifling, because our knowledge of the true structure of the 
fossil is exceedingly imperfect. 
In the present case (Euomphalus or Solarium), speaking simply as 
a geologist, it appears to me that all useful purposes will be served by 
retaining the same generic name for all the varieties, and dividing the 
genus into three subdivisions, as follows: — 
EUOMPHALUS. 
Type A.—Elat-spired; provided with breathing tubes like the Halio- 
tidse. Type species :— 
1. Euomphalus cristatus. 
2. Euomphalus G-oldfussi. 
Type B.—Eaised spire; provided with a deep slit in the exterior 
lip, and a sinus band on the shell. Type species :— 
1. Euomphalus Eeginse (Haughton). 
Type C.—Ordinary flat spired, smooth forms of Euomphalus. Type 
species :— 
1. Euomphalus pentangulatus. 
2. Euomphalus pugilis. 
DESCRIPTION OF PLATES III. AND IY. 
PLATE III. 
Eig. 1. Under side of unique specimen of Euomphalus cristatus (Phillips), 
preserved in the Museum of Trinity College; locality not cer¬ 
tain, but believed to be Strokestown, county of Eoscommon. The 
figure shows the tubular character of the crests, which are closed 
below; their upper surface is not known. 
Eig. 2. Natural cast of same, taken from the upper surface of the lime¬ 
stone slab. The original, exclusive of the spines, is eight inches 
(nearly) in diameter. 
PLATE IV. 
Eig. 1. A specimen of Euomphalus acutus (Sowerby); somewhat distorted 
by cleavage, probably from Little Island, county of Cork : this 
specimen belongs to the Museum of the Eoyal Dublin Society. 
It is remarkable for the semicircular sinuosity observable on the 
lines of growth in passing the keel of each whorl, which must 
have corresponded with a notch in the outer lip. There is, how¬ 
ever, no sinus, as observable on Eig. 2. 
