Structure of Paleozoic Barnacles. — Clarke. 
139 
toward the ventral side of the body. This latter feature alone 
demonstrates, so far as comparisons can be drawn between 
this fossil and the living Thoracica, that Strobilepis at least 
includes the so-called capitular portion of the shelled bar¬ 
nacles. 
The genus Lepidocoleus was introduced by Charles L. 
Faber* for a cirripede from the Hudson River rocks at Cincin¬ 
nati. According to Mr. Faber’s identification the species 
upon which the genus is based is that described from isolated 
plates by Hall and Whitfield as Plumulites jamesi.\ The 
Cincinnati specimen is apparently entire and shows very dis¬ 
tinctly the points of structure upon which the generic diag¬ 
nosis is based. The fossil consists of but two vertical rows 
of plates and these are so arranged as to exclude the possibil¬ 
ity of any additional accessory rows. These plates have 
reversed symmetry and corresponding ones are of the same 
size, but each is decidedly unsymmetrical in itself. The 
apices are situated at one edge (which Mr. Faber has accur¬ 
ately termed the dorsal edge) of the flat body and thus those 
of the two rows lie in close apposition. From this apex there 
is a very short slope on the narrow dorsal surface and a very 
long slope over the side to the ventral edge. The fine orna¬ 
mental lines are concentric to the apex and thus increase the 
appearance of asymmetry in the plate. The plates in each of 
the two series overlap each other for one-half or two-thirds 
of their length so that but a narrow portion of each is exposed. 
The members of the two rows alternate with regularity at the 
dorsal edge so that the individual plates do not occupy 
symmetrical positions, each being a little further forward 
than that most closely adjoining it on the opposite row. On 
the dorsal edge the elevation of the apex is continued into a 
slight thickening or ridging of the ante-lateral slope of each 
plate. The plates of the two series come together in direct 
apposition without overlap on the ventral edge. The resultant 
form of the fossil is, hence, elongate blade-shaped, with broad 
sides, a narrow dorsal and sharp linear ventral edge. Faber’s 
specimen also shows a strong flexion of the three or four basal 
plates toward the ventral side. The author gives no details 
*Journ. Cinti. Soe. Nat. Hist., p. 14, pi. 1, figs. A-F : 1887. 
fPalseont. Ohio, vol. 2, p. 106, pi. 4, figs. 1. 2. 
