337 
ON SOME PALiEOZOIC OSTRACODA FROM 
PENNSYLVANIA, U. S. 
By Peofessob T. Rupekt Jones, 
F. R. S., F. G. S., Corresp. Memb. Acad. Nat. Sci., Philadelphia, &c., Ac. 
[With Plate*]. 
A collection of Palaeozoic Ostracoda, collected by Prof. E. 
W. Claypole, F.G.S., of Buchtel College, Akron, Ohio, during 
his work on the Geological Survey of Pennsylvania, having 
been sent to me by him for examination, the present notes 
and plate are supplied for their identification. 
CONTENTS. 
I. Devonian. 
^KSilaTiSja i upper Devonian. 
3. Bythocypris favulosa, ) 
4. Bolliauugula, > Lower Devonian. 
5. Primitia pennsylvanica. ) 
II. Silurian. 
1. Bythocypris oviformis, i 
2. Leperditla subquadrata. > Lower Helderberg. 
S. Klcedeuia pennsylvanica. ) 
I. Devonian Species. Figs. 1, 2, 10-15. 
I. PRIMITIA MUNDULA Joiies. 
Some of the soft, brownish, mottled, argillaceous limestone 
of the Upper-Devonian Chemung-Catskill shales at King's 
Mill, Perry county, Pennsylvania, abounds with Prhnitia 
mundula, varying in size, and more or less in outline, and in 
the proportions of the sulcus. Some are only .75mm., or less, 
in length; the largest are 1.25mm. long and beautifully retic- 
ulate. These closely resemble some from the Lower-Devonian 
strata of New Brunswick,' but are rather longer in proportion 
to the bight. In a letter Prof. E. W. Claypole refers to this 
rock as a rough, rudely stratified shale, with the Entomostraca 
{Prlmitice) in little nests between irregular layers of the shale. 
"With these Prhnitiiv here and there occur some small 
white bivalve shells, mostly subtriangular, and all bearing 
concentric ridges, rather wide apart. They are mostly smooth, 
but some show traces of delicate reticulation. Hence there 
is some resemblance to Estheria, but there appear to be more 
than one kind, and several have a strong vertical depression 
or sulcus just below the umbo. Their alliances are obscure. 
• This plate was drawn with the aid of a grant from the Royal Society 
of London. 
' Such as figs. 1 and 2, a. b. pi. 10, "Artn. Mag. Nat. Hist." Scr. 6, 
vol. Ill, 1889, p. 375, &c. 
