Agelacrinidae and Lepadocystinae 
463 
very small plates. The space belonging to the inner circle is 
occupied by a circular mass^ half a millimeter in diameter, within 
which it is impossible to distinguish any individual plates. Possi- 
bly this part of the anus was more or less retractile. It is very prob- 
able that the outline between plates 13 and 19 was drawn incor- 
rectly in this diagram. Judging from other specimens, plate 19 
never should be in contact with the anal area, in this species, and 
the lower left hand part of plate 19, as illustrated in this diagram, 
unquestionably belongs to the adjacent part of plate 13. The 
line of separation between plates 19 and 13 should be drawn along 
the left border of the ambulacrum or subvective system. Judging 
from other specimens, the difficulty of distinguishing the outline 
between plates 19 and 13 arises from the fact that this outline 
frequently is covered by the. left margin of the ambulacrum, which 
does not cross the middle of plate 19, as here drawn in the dia- 
grams, but traverses the left half or left two-thirds of the plate 
instead. In each of the diagrams here presented the effort was 
made to interprete the specimen on the basis of what the specimen 
actually appeared to suggest, irrespective of every other specimen. 
In the case of the present diagram, the supposed outline between 
plates 19 and 13 probably is due to a crack crossing plate 13, and 
the covering up of the real line of separation by the ambulacrum 
crossing the left part of plate 19. Owing to the difficulty of dis- 
tinguishing plates 20 to 24, the outlines here presented have little 
value. Stereom-folds in pectinirhombs 1-5, 12-18, 14-15, 10-15, 
about eleven; in pectinirhombs 11-17, about seven. These num- 
bers disagree with the number of stereom-folds found in speci- 
mens of larger size, which resemble the type in having a parallel- 
line ornamentation, instead of a stellate plate ornamentation. 
That part of the Dyer Collection acquired by Miami University 
contains also another specimen of Lepadocystis, with the theca 
broken across so as to expose the interior of one side. Interior 
views of pectinirhombs 1-5, and 11-17 are presented. These pec- 
tinirhombs project angularly into the interior cavity, the stereom- 
folds passing uninterrupted from plate to plate, and are not dis- 
crete, as on exterior view. The stereom-folds on pectinirhomb 
1-5 number about eleven, and those on pectinirhomb 11-17 
number seven. Both an exterior view of the column and of its 
area of attachment on the interior of the theca are presented. 
The column is rather large at its area of attachment, and tapers 
