Agelacrinidae and Lepadocystinae 
457 
produced on this page as Figure 2. In Lepadocystis, from the 
upper Richmond of Indiana, the gut apparently has been raised 
sufficiently to cause the disappearance of the pore-rhombs on the 
middle parts of plates 12, 11, 10, and 14; also on the lower parts of 
plates 10 and 14 and on the adjoining upper parts of plates 8 and 
9. This lifting of the gut was accompanied both by a lifting of 
the anus and also by a shifting this anus toward the right. The 
anus was lifted from between the second and third row of plates to 
a position within the third row, pushing plate 13 upward to a 
position between plates 18 and 19, and crowding plates 18 and 
17 toward the left, altering their primitive pentagonal outline to 
Fig. 2. The actual distribution of all pore-rhombs known with certainty in the 
Glyptocystidae, showing how a space is left clear where the gut may be supposed 
to have pressed against the thecal wall. Copied from Bather, in Caradocian 
Cystidea from Girvan, 1913, page 437. 
a more quadratic form. The migration of the anus toward the 
right appears to be connected with the dextral curvature of the 
gut within the visceral cavity. At any rate, there does not seem 
to be any cystid in which the anus may be supposed to have 
travelled toward the left. 
In Brockocystis, from the Silurian of Ontario, the anal area 
occupies a position similar to that of Lepadocystis, but it is larger, 
and has not thrust plate 13 as far upward, so that this plate does 
not come in contact with the sides of plates 18 and 19 but only with 
their lower margins. The absence of the pore-rhomb on plates 
11-17 suggests a local upward flecture of the gut in this area. 
