ORDOVICIAN FAUNAS. 187 
HOLOPEA PARVULA Ulrich. 
Plate XII., Fig. 30. 
189%. Holopea parvula Ulrich, Pal. Minn.,’pt. I1., p. 1067, pl. 79, 
fre. 19 (ff. pyrene var. parvula in explanation of plate). 
Description.—‘Shell small, 6 to 10 mm. in width, the height equal- 
ing about three-fourths of the width; spire depressed-conical; whorls 
four, including two very small ones at the apex, neatly rounded, sub- 
circular in section; suture distinct, very slightly canaliculate; um- 
bilicus large, equaling about one-fourth of the diameter of the shell; 
aperture moderately oblique, rounded, slightly modified above by the 
preceding whorl; surface with very fine, obscure lines of growth, 
and on the latter half of the body whorl a number of more or less 
obscure undulations running parallel with the apertural margin.”— 
Ulrich. 
Remarks.—Among the New Jersey specimens a single one seems 
*to be a member of this species. It is imperfectly preserved, but, in 
so far as its characters can be determined, it does not differ essentially 
from Ulrich’s description, which has been copied above. The um- 
bilicus is so filled with the matrix that its size cannot be determined, 
the surface marking cannot be seen, and none of the obscure undula- 
tions mentioned in the description can be detected. 
HOLOPEA SUPRAPLANA U. & S.? 
Plate XII., Figs. 31-82. 
1897. Holopea supraplana U. & S., Pal. Minn., pt. IL., p. 1068, pl. 
79, figs. 27-28. 
A single imperfect specimen from New Jersey, from which all the 
inner whorls are missing, seems to be referable to this species. It is 
characterized by its rapidly-expanding, outer volution, the vertical 
expansion being much the most pronounced, so that the aperture is 
nearly twice as high as it is wide. 
