88 
Aug. F. Foerste 
a droite et a gauche d’une subechancrure mediane, une bourrelet pen 
considerable, crenele ou dentele transversement ; aucun indice de support. 
Ex. La Strophome7ie rugueuse, Strophomena rugosa, Rafin., pi. LIII, 
fig. 2. 
Observ. Ce genre, propose par M. Rafinesque, ne contient encore que 
des especes fossiles, au nombre des trois, suivant M. Defrance. 
The following is a free translation: 
Animal altogether unknown. 
Shell regularly symmetrical, equilateral, with valves nearly equal in 
size; one valve fiat and the other a little concave; hinge line straight, 
transverse, presenting, on the right and left of a sort of median V-shaped 
groove (formed by the hinge-areas), a small, moderately prominent ele- 
vation (the deltidium and chilidium), having a crenate or dentate out- 
line when examined transversely; no indication of a means of support 
(pedicel). 
The original figures were reproduced by Hall and Clarke in 
vol. VIII of the Paleontology of New York, page 247, in 1892. 
However, the copy of the pedicel valve presents only 72, instead 
of 92 radiating striae, and the postero-lateral angles are repre- 
sented as more rectangular than in the original figure. More- 
over, the figure of the brachial valve, showing also the hinge-area 
and deltidium of the pedicel valve, presents only 63 instead of 
94 radiating striae, and fails altogether to show the distinct down- 
ward flexure of the marginal parts of the shell for a distance of 
fully 3 mm. from the anterior margin, and 2J mm. from the 
lateral margin of the shell, as far back as the hinge-area, produc- 
ing a geniculate downward depression of the shell all around the 
margin, beginning at an elevated concentric wrinkle, which is 
bordered posteriorly by a moderate concentric depression. The 
large size of the deltidium of the pedicel valve is brought out by 
Hall and Clarke’s figure, but the lateral outlines of this deltidium 
are slightly convex instead of slightly concave. 
In the Dictionnaire des Sciences Naturelles, vol. LI, page 151, 
published in 1827, Defrance gives the following description: 
Strophomene rugueuse; Strophofnenes rugosa, Rafinesque. Coquille 
bombee en dessous, et dont la valve superieure est un peu concave et 
chargee de petites stries rayonnantes. Largeur, un pouce. Fossile 
de I’Amerique septentrionale. On voit une figure d’une coquille de 
cette espece dans Tatlas de ce Dictionnaire, planche des fossiles. Des 
coqu files de ce genre, qu^on trouve a Dudley en Angleterre, ont de tres- 
grands rapports avec cette espece; elles en different pourtant en ce que 
