Vol. 58. ] PHYLLOCARIDA FROM PENNSYLVANIA. 44] 
27. Revision of the Puytuocaripa from the Coemune and WAVERLY 
Groves of Pennsytvanta. By Prof. Caartes Emerson BEEcHER, 
Ph.D., F.C.G.S. (Read April 30th, 1902.) 
[Puates XVII-XIX. ] 
Ir is now eighteen years since I prepared a memoir for the 
Second Geological Survey of Pennsylvania, describing the species 
of Phyllocarida then known from the Chemung (Upper Devonian) 
and Waverly (Lower Carboniferous) Groups in that State. Subse- 
quent collecting at the original locality has yielded a quantity of 
material which further elucidates the characters of the original 
species, and also adds two distinctly new forms to the fauna of 
the Waverly Group. 
The specimens described in the present paper, as well as those 
on which the original descriptions were based, were all obtained in 
the vicinity of Warren (Pennsylvania). The chief horizon is in the 
shale-beds of the Upper Chemung Group, about 50 feet above mean 
water-level in the Alleghany River. At this level, crustacean 
remains are fairly abundant, and constitute a conspicuous element 
of the contained fauna. On this account, the deposits have been 
called by me ‘the Phyllocarid-Beds.’ The species thus far secured 
from the horizon are Echinocaris socialis, T'roprdocaris bicarmata, 
and Hlymocaris siliqua. Other forms are much less abundant, and 
occur in a sporadic manner in the higher strata. 
The following notes on the genera and species are to be considered, 
not as complete descriptions, but as additions and emendations to 
the original diagnoses. 
Ecutnocaris socratis. (Pl. XVII & Pl. XVIII, figs. 1-7.) 
_ Echinocaris socialis, Beecher, ‘Ceratiocaride from the Chemung & Waverly 
Groups of Pennsylvania’ 2nd Geol. Surv. Penn. vol. PPP (1884) p. 10; Hall & 
Clarke, ‘ Palzont. of N. Y.’ vol. vii (1888) p. 174. 
The new material representing this species, consisting of more 
than a hundred individuals, presents a greater range in size than 
was originally observed, and permits of a more exact description of 
the postabdomen, the ornamentation of the somites, and the number | 
of lobes in the cephalic areas. In addition, the position and character 
of the mandibles can now be determined. 
The telson has the form of an abdominal somite, with a carinated 
extension behind, forming the spine (Pl. XVIII, fig. 3). The rows 
of spiniform nodes so characteristic of the other somites are absent. 
On each side of the base of the telson-spine are the articular faces. 
for the cercopods, the dorsal pivotal points being marked by a node. 
The cercopods are about one-fourth longer than the telson-spine, 
and have a groove on their inner side, probably for the insertion of 
a row of setze, as in Mesothyra oceani, Hall & Clarke.’ 
1 * Paleont. of N. ¥. vol. vii (1888) p. 187. 
