1896. ] NEW YORK ACADEMY OF SCIENCES. 199 
ward to describe Turrilepas, or J. M. Clarke Strobilepis, or C. 
L. Faber Lepidocoleus, or J. Barrande Plumulites, but when 
similar objects are found in the Cambrian system no doubt these 
genera will throw light upon them. 
The remains found in the Cambrian rocks of eastern North 
America are only scattered plates of the exoskeleton, and they 
are described largely with the object of inviting attention to the 
plates of this kind, not at all rare in some layers of the fine 
shales of the Lower Cambrian, which appear to be referable to 
Cirripedes. Of the genera mentioned above Plumulites appear 
to be recognizable in certain plates found in the Paradoxides 
beds of Newfoundland. 
PLUMULITES Barrande. 
In 1846 Barrande observed in the Ordovician rocks of Bohemia 
some peculiar plates of sub-triangular form and strongly ribbed 
transversely, which he called Plumulites. Eleven years later he 
found plates of this kind grouped together in such a way as to 
show the kind of animal to which they had belonged. In 1864 
Prof. Reuss, in connection with a memoir on the Lepadide of 
the Oligocene of Germany and chalk of Gallicia, took occasion 
to point out that the Plumulites of Barrande were remains of 
Cirripedes.* In 1865 Dr. Woodward referred the valves 
from the Silurian beds of Dudley, Eng., which de Koninck had 
called Chiton Wrightianus to the Cirripedes under the name of 
Turrilepas. 'Thus by degrees the proper zodlogical position of 
these peculiar valves or plates, usually found loose and scattered 
in the shales of the Paleozoic rocks, came to be recognized. 
Barrande’s description of Plumulites is somewhat diffuse, and 
has been summarized by Zittel as follows:+ Body elongated, 
resembling a pine cone, clothed with 4-6 (or more) longitudinal 
series of scaly plates. The plates are covered by strong trans- 
verse striz, somewhat in relief, and have a triangular form ; the 
median series are ordinarily distinguished from the lateral by 
their more convex form, and by the presence of a median keel. 
Barrande also found a peculiar, more oval valve in which the 
striz encircled the upper end, which valve he called valve fenés- 
tré. 
Plumulites has been found in the Ordovician (where it was 
first recognized) of Bohemia and Ohio, and similar plates in the 
Silurian of England and the Devonian of New York; it has not 
hitherto been reported from the Cambrian. 
The presence of so highly differentiated a class of Crustaceans 
*Syst. Silur. Bohéme vol. i., Supp. p, 566. 
+ Traité de Palzontologie. Zittel and Barrois. vol. ii., p. 533. 
