444 
Aug. F. Foerste 
be considered a well established species. It has already been 
noted that the specimen described by Meek in the Paleontology of 
Ohio, vol. 1, p. 55, in 1873, from the upper part of the Richmond 
group, at Richmond, Indiana, probably belonged to the same 
species. Its nearest relative appears to be Agelacrinus pileus. 
33. Agelacrinus austini, sp. nov. 
{Plate VI, Figs. 1A,B,C.) 
This species is characterized chiefly by its small size. The 
largest specimen at hand does not exceed 10 mm. in diameter. 
The upper surface is of very moderate convexity. In a specimen 
8.5 mm. in diameter (hg. lA on plate VI), that part of the ray 
which is parallel to the inner band of the peripheral ring is about 
as long as the straight, proximal part, radiating directly from the 
oral center. In a specimen 7.5 mm. in diameter (fig. 1C, on 
pi. VI), the rays are more gently curved and meet the peripheral 
ring at an acute angle without being strictly parallel to it for any 
distance. In a still smaller specimen, 6.5 mm. in diameter 
on the same support as the original of figure 1C, the left posterior 
ray. No. 1, is almost straight, and the remainder are but very 
moderately curved, meeting the peripheral ring at rather obtuse 
angles, compared with the rays of larger sized specimens. The 
exposed part of the lateral covering plates is ovate-triangular 
in form, and the spaces between adjacent plates are occupied 
in each case by one of the central or median series of covering 
plates, of which a relatively greater length frequently is exposed 
than in the case of any other known species. Commensurate 
with the small size of the specimens, the number of the squamose 
interambulacral plates is rather small. The anal pyramid 
consists of an outer circle of 6 ovate-triangular plates, between 
which can be seen glimpses of an inner circle, probably of about 
the same number. The inner band of the peripheral ring con- 
sists of one circle of large plates, considerably extended laterally. 
Above this is a circle of smaller plates graduating into the inter- 
ambulacral series; and below is a third series graduating into the 
successively smaller plates forming the outer or marginal part 
of the peripheral ring. 
The conspicuousness of the larger plates of the inner band of 
the peripheral ring of Ordovician species referred to Agelacrinus 
