;;n| The American Geologist. November, 1893 
above two plates, five to six sided. A short arm -like plate 
rests upon each of these firsl radials of the second series. No 
higher plates preserved on the type specimen. 
First interradial plate hexagonal, length and width equal 
and resting between the upper sloping sides of the first radi- 
als and the lower lateral sides of the second radials. Next 
-cries of two plates; third, three; fourth, four, (smaller. Vault 
and interradial plates meet in such a manner as to make it 
difficult to say where the latter cease and the former begin. 
First azygous interradial is quite as large as first radials. and 
heptagonal. In all there seem to be but thirteen plates in 
the azygous area, rather irregularly arranged, three forming 
a straight line and surrounded laterally and above by a horse- 
shoe-shaped figure of eiyht somewhat smaller plates. Vault 
plates rather large, polygonal, strongly tumid. Vault slightly 
sunken. Base of a rather slender, almost lateral anal tube. 
Calyx plates not only strongly tumid, but each of the larger 
ones supports a conspicuous central spiniferous node. 
The radiating ridge-like ornamentation so characteristic of 
the calyx plates of this genus of crinoids is almost wanting 
in this species, appearing as short cross-bars along the lines of 
plate union. Column, rays and arms unknown. The first was 
seemingly rather small compared with the great body. Hight 
o|' the body L^ inches, greatest breadth 1 ^ inches. 
The great size of the body of this species, the strongly 
tumid character of all the body plates, the very conspicuous 
central spines of the the larger calyx plates, and the almost 
entire absence of the usual ornamentation of this genus, will 
serve to characterize this magnificent crinoid. 
Collected from the Hamilton beds of Callaway Co., Mo., and presented 
to the author by Mr. D. K. Greger, in whose honor the specific name is 
given. 
There is a much smaller species of Melocrinus, associated with M. 
gregeri, in Callaway Co., which has less tumid plates, but is provided 
with spine-like nodes and short radiating ridges, noticeable only near 
the lines of union of the plates. 
Taxocrinus concavus (now tp.). 
(Plate xiv, fig. 2. Side \iew of the body, natural size.) 
Calyx, a low. Hat cup. Base concave, so that on a side view 
only the tips of the basals can be seen. A stem joint obscures 
