472 
Aug. F. Foerste 
and in one specimen, this space was transversed by thin circular 
sheets of sclerodermous material, one sheet for each columnal, 
extending from the column diagonally upward toward the pitted 
surface. These thin annular sheets are fluted radiately, the 
fluting possibly having some connection with the reticulated 
surface markings. Adult animal probably eleutherozoic. 
Ambulacral or subvective system coarse, confined to the 
extreme top of the theca, Ambulacral grooves strong, about a 
millimeter wide at their proximal ends, uniting at the center of 
the tegmen in an oral orifice nearly 2 mm. wide and a little over 
1 mm. in diameter in an antero-posterior direction. This orifice 
descends into the theca, but probably was entirely concealed by 
covering plates, as in the closely related genus, Lepadocystis. 
No trace of covering plates, however, remains. 
The trimerous origin of the ambulacral system is clearly defined. 
The anterior ambulacrum is directed toward the right of a line 
drawn perpendicular to the line connecting the terminations of 
the lateral primary ambulacral grooves. It extends 4.5 mm. from 
center of the tegmen almost to the adjacent proximal angles of the 
pectinirhombs on plate 15. The lateral primary grooves bifurcate 
about 1 mm. from the oral passage or 2 mm. from the center of the 
tegmen. The right anterior ambulacrum terminates on plate 16, 
about 6 mm. from the center of the tegmen, and is almost a direct 
continuation of the right primary division of the ambulacral system. 
The right posterior ambulacrum curves strongly backward and to- 
ward the left, terminating on plate 17, about 5.5 mm. from the cen- 
ter of the tegmen . The left posterior ambulacrum is directed diago- 
nally backward to plate 18, terminating about 7 mm. from the center 
of the tegmen. The right anterior ambulacrum curves forward to 
plate 19, and terminates 7 mm. from the center of the tegmen. All 
of the ambulacra are broad at their proximal ends and bluntly 
triangular in form. In each case one or more ambulacral plates 
are missing. Judging from those remaining, the number of brachi- 
oles on each side of each arm usually was two, but may in some 
cases have equalled three, or may even have been reduced to one 
on one side. The proximal one of these brachioles, judging from 
the facets, probably was coarse, and the distal brachiole, at least 
smaller. 
