116 
THE GEOLOGIST. 
Fig. 3. Producta mimrrosa, Sow. Internal cast of tlie ventral valve, from the 
JMagne.sian Limestone t)f the Carl>uniferous series of Breedon, 
Leia'stershirc. A and C, ucclnsor, H, divaricaioi- muscular 
impressions. L, cones, ■\vliicli denote the :lcep liollows which 
exi.sted in the interior of tlie immensely thickened ventral 
valve, and wiiich were occujjied hy the spiral arms. 
4. Aidosterjes Wangenheimii, <le Verneuil and de Keyserlin;;', Sp. From the 
Permian Limestone of Mount Greheni, in Kussia. 
5. ,, Wangenheimii. Interior of the dorsal valve (enlarged). J, 
cardinal process. A, occlusor muscular impressions. W, 
oral processes (?) of Woodward. X, Reniform impressions. 
I am indebted to General Ilelmersen for these two beautifid 
examples. 
6. Strophalosia laniellosa, Geinitz, var. Morrisiana, King. From the Mag- 
nesian Limestone of Tunstall Hill (Durham). II indicates 
the portion of the beak which adhered to marine bodies. 
7. ,, Goldfimii, ]\Iiinster. A very remarkable interior of a dorsal 
valve, recently discovered by Mr. Kirkby, and forming part 
of his valuable collection oi' Pernuan fossils. The occlusor 
and reniform impressions project to an unusual extent. The 
sockets for the articulatinn of the valves are clearly seen on 
either side of the cardinal process, J. 
8. „ Goldfussii, internal cast of the ventral valve, from the Mag- 
nesian Limestone of Humbleton Hill ; showing the occlusor 
and divaricator muscular impressions. 
9. 9°. CJionetcs Prattii, N. 8p. {'.) Nat. size. This beautiful specimen (from 
the collection of Mr. Pratt) is here given as an illustration of 
the genus, on account of the admirable preservation of its 
valves. The specimen is silicified, and the valves can be as 
easily separated as in those of a recent sjiecies. Its locality 
is unfortunately unknown. The ventral valve is veiy deep, 
with a longitudinal depression along its middle ; the dorsal 
valve is almost Hat, with a small elevation towards the front ; 
both valves are covered with minute striae. 
10. „ A portion of the same, magnified, to show the area of both 
valves ; pseudo-deltidium, and cardinal process. 
11. „ Interior of the ventral valve ; A, occlusor, R, divaricator 
muscular impressions. The cardinal spines and their tubuli- 
form orifices are here clearly exhibited. 
12. ,, Interior of the dorsal valve ; j, cardinal process ; A, and A', 
anterior and posterior occlusor muscular im])ressions ; o, 
ovarian spaces (?) ; X, reniform imjiressions. The granular 
prominences (described in the text) are here beautifidly 
exhibited. 
13. Strophomena rhomboidalis, Dalman. Showing the position of the occlusor 
and divaricator muscular impressions, as well as two coiiical 
subspiral prominences, L, which I suppose to have been 
produced Ijy the mantle jn-essing upon the spiral arms, ( 0 as 
already described in the same valve of Baridsonia. Enlarged 
from a specimen in Queen's College, Galway, and wliich was 
originally communicated to me by Professor King. 
14 & 14°. StrjpJiodonta demissa, Conrad, Sp. Exterior of both valves ; 
from the Hamilton Group of Western New York, America. 
Fig. 14 shows that no fissure or itseudo-deltidium interrupted 
the regularity of the area in either valve ; also the small, 
longitudinal stri;e with which it is covered. 
demissa. Interior of the ventral valve (enlarged), to show the 
teeth and small testaceous projections between them. A, 
occlusor, R, divaricator muscular impressions. 
dem.iisa. Interior of the dorsal valve. J, cardinal process. 
15. 
16. 
I 
