Agelacrinidae and Lepadocystinae 
467 
the adjacent angle of plate 12. Several of the ambulacral plates 
have dropped off from the theca. Of the ambulacrum on plate 18, 
only the proximal plates remain. The others have dropped off 
from the theca, but the flattened area on the latter indicates that 
the right side of this ambulacrum formerly covered the suture 
between plates 18 and 13, and that the tip of this ambulacrum 
reached at least the lower right hand angle of plate 18. From the 
center of the tegmen, the anterior ambulacrum, on plate 15, 
extends 3.5 mm.; the right anterior ambulacrum, on plate 16, 
6 mm.; the right posterior ambulacrum, on plate 17, 5.5 mm.; the 
left posterior ambulacrum, on plate 18, 6.5 mm.; and the left 
anterior ambulacrum, on plate 19, 7 mm. Judging from the ele- 
vations at the attachments for the brachioles, the number of 
brachioles on each side of the anterior ambulacrum were about 
three or four; on each side of the right anterior ambulacrum, about 
five or six ; on each side of the left posterior ambulacrum, about 
six or seven; and on each side of the left anterior ambulacrum, also 
about six or seven. The right posterior ambulacrum is not suffi- 
ciently preserved, but judging from its length it probably had five 
or six brachioles on each side. 
The outlines of the deltoids, or plates belonging to the fifth row, 
are more readily detected in this specimen than in any other, and 
the result is indicated in the accompanying diagram. 
Stereom-folds in pectinirhomb 1-5, unknown; in pectinirhomb 
12-18, nineteen; in pectinirhomb 14-15, twenty-one; in pectini- 
rhomb 10-15, about sixteen; and in pectinirhomb on plates 11-17 
about ten or eleven. 
At the lateral ends of the pectinirhombs, the stereom-folds often 
are continuous across the suture lines, exteriorly as well as inte- 
riorly, but along the middle of the rhomb there is a lens-shaped area, 
including parts of both plates along the suture lines, in which the 
folds are not visible. From this lens-shaped area, the stereom- 
folds on plates 10, 11, 12, and 14 slope downward, and on plate 5 
slope upward, both the upper and lower lip of the fold area being 
sharply defined by a raised border. On plates 15, 17, and 18 
the stereom-folds slope upward, and here only the upper lip is 
sharply defined. In a similar manner, the stereom-folds on plate 
1 slope downward and are strongly defined only along the lower lip. 
The anal area presents evidence of at least two circles of plates, 
of which the interior one forms the conical pyramid. Apparently 
