406 
Aug. F. Foerste 
7 . Supporting Surface of Agelacrinus Cincinnatiensis 
Probably More Horizontal than in A. Pileus 
An examination of a number of specimens of Agelacrinus cincin- 
natiensis has failed to bring out as strong a connection between the 
orientation of the individuals and the direction of the slope upon 
which these individuals were located, as was noted in the case 
of Agelacrinus pileus, and Agelacrinus holbrooki. Agelacrinus 
cincinnatiensis is a larger and flatter species than Agelacrinus 
pileus. The former frequently attained a diameter of 30 mm., 
occasionally of 33 or even 35 mm. The latter usually did not 
exceed 15 mm. in diameter, although specimens 20 mm. in diameter 
have been noted. The specimens of Agelacrinus cincinnatiensis, 
being of larger size, covered a much larger part of the valves of the 
Rafinesquina upon which they rested, and, therefore, were not 
likely to find a sufficiently large surface unless the valve was more 
or less horizontal, and not partly imbedded in the mud on the sea 
bottom. A moderate amount of sagging of the theca, after death, 
however, was noted. In these cases, the upper part of the pe- 
ripheral outline is flattened and extended, while the lower part of 
this outline is shortened, as in Agelacrinus pileus, but to a less 
marked degree. 
8. Solar Curvature in the Devonian Agelacrinites 
AND LePIDODISCUS 
The preceding remarks are based upon an examination of the 
Ordovician specimens referred to Agelacrinus or Lepidodiscus . 
They do not take into account the Devonian Agelacrinites hamiF 
tonensis, with both the right (No. 4) and the right posterior ray 
(No. 5) solar (plate VI, Fig. 3), or Lepidodiscus alleganius, with 
all the rays solar (plate VI, Fig. 2A). The remarks evidently 
are based on highly speculative inferences, but they at least sug- 
gest that some of the characteristics of various species of Agela- 
crinus, may be produced by the orientation of the animal while 
resting upon some support, especially while engaged in feeding. 
It may be assumed that the main business of the animal while 
in life consisted in feeding. 
