182 Review of Geinitz on the rocks and fossils of Nebraska. 
Aucella Hausmanni Goldf. Geiniis ib., fig. 8. This is doubt- 
Giclisertase from the Missouri Coal- -measures. I have also seen 
a similar form from beds in Nova Bectia, referred by good au- 
thorities to the Sub-carboniferous 
Mytilus concavus? Swallow. Gsinits, ib., fig. 9. This is not 
the form described by Prof. Swallow, which has angular instead 
of rounded umbonal slopes. It may be a Myalina but it is cer 
tainly not a true Mytilus. 
Myalina perattenuata M. & H. Geinitz, “ib, fig. 10-11. Cor- me 
rectly identified, but it is specifically distinct from M. permiana | 
= (cited by Geinitz as synonym), which has less attenu- 
ated be 
Myalina subquadrata Shumard. Geinitz, ib., figs. 25 and 26, | 
Correctly identified. It is common in the upper Coal-measures | 
of — region, and has been found by Dr. White in thesam@ 7 
horizon in Iowa. - 
Astoula speluncaria Schlot. —_ = , fig. 12. As already | 
stated, this belongs to Beyrich’s s Pseudomonotis. The | 
specimen figured by Prof. Geinitz is eat from Nebraska, but 
was sent to him by Prof. Dana from the Permian beds of Kat 
s, and is the same shell described by Dr. Hayden and the 
meter under the name Monotis Hawni.* It nearly resembles 
the European ae speluncaria, and may possibly be identiesh 
but | opean specimens of that species now before me 
can be distinguished from the American form. At any rate We 
have a specimen from a bed of nearly black limestone, far down 
in the Coal-measures at Leavenworth, Kansas, agreeing eve? 
more nearly with P. speluncaria than P. Hawni does. Similar 
forms occur at different horizons in the Coal-measures and Per 
mo-carboniferous beds in Kansas, and have been found in the 
Upper Coal- pen i of Iowa, by Dr. White. of 
nneformis Geinitz, ib., fig. 13. From speciaeny 
the shell se to me by Dr. White from the same horizon if 
Iowa, I am sure it is specifically distinct from the so-called A. 
and there can be little doubt that it even belongs 
the distinet — Pinna 
ep Sess: as 
_* The Hee ies nia Pseudomonotis 
: pecs to be a variety of the same but probably distinct, eo é 
fe See (See si uaseetoten titi) 
