II- The American Geologist, March, 1896 
phase parallel to the primitive condition of structure repre- 
sented by Lepidocoleus. 
A third species of Lepidocoleus, L. polypetalus, occurs in 
the shaly limestone of the Lower Helderberg group. The 
singled observed specimen, which is from Albany county, N. 
Y., is incomplete, being broken at both extremities and some- 
what obliquely crushed, so that only a portion of one of the 
broad sides is exposed for the principal part of the specimen, 
the dorsal margin with the approximate apices of the valvu- 
lar plates being on the under side of the specimen, only a part 
of which has been set free from the matrix. Toward the 
upper <u- distal end of the specimen are three plates which 
retain their convexity. This species is very much larger than 
either of the others and the fragment bears seventeen plates. 
Evidently several more are needed to complete the test. This 
is a number considerabl} 7 in excess of what seems to have 
been the full number in the other species, and we are led to 
infer, from the apparent approximate completeness of the 
other specimens, that the number of plates varied with the 
species. The specimen of L. polypetalus though showing a 
slight basal curvature has this feature not very well developed, 
probably from the absence of the basal plates. The greater 
size of the species is not, however, wholly due to the greater 
number of plates; the plates themselves are individually lar- 
ger than those of the other species. The original fragment 
has a length of 35 mm. 
It is not likely that this primitive, slightly modified cirri- 
pede structure represented by Lepidocoleus should be closely 
classed with forms like Strobilepis and Turrilepas which are 
provided with four or more vertical rows of plates. The pre- 
sence of accessory rows between the major series, one on the 
dorsum and another on the venter, must have involved an 
essential modification of function, if in no other way, by closing 
the ventral aperture for the protrusion of the appendages. It 
is far easier to conceive the relations of the animal to the shell 
in Lepidocoleus than in the case of these multiseriedcirripedes. 
Authors and compilers have generally included Turrilepas with 
Lepadidai, and yet the relations of the fossil and its ally 
Strobilepis to Lepas, L<>ricnl<i or any typical member of the 
