338 THE CRINOIDEA CAMERATA OF NORTH AMERICA. 
c 
as the radials; they are widest next to the intercostal sutures, tapering to 
both ends; the lower lateral faces convex, and longer than any of the 
others; the upper faces meeting the interbrachials of the second order. The 
two latter plates combined are but little smaller than the lower one, their 
tips rising conspicuously above the arm facets, and very little truncated. 
Interdistichals much smaller than the corresponding interbrachials, their 
lower ends touching the costals or resting between the upper sloping 
faces of the distichals. The remaining parts of the species are not shown 
in the specimens, but it may be suggested from the condition of the inter- 
brachials and interdistichals that the partition walls were unusually thin. 
Horizon and Locality. — Niagara group; Waldron and Hartsville, Ind., 
Lockport, N. Y., and Racine, Wis. 
Types in the Museum of Comparative Zodlogy. 
Remarks. — Miller and Dyer, in their specific description, after giving 
the structure of the brachials, and stating that the first interbrachials are 
“nine or ten-sided,” continue as follows.: “This description applies to the 
two ten-sided interradials; the other three have only nine sides, as shown 
by Plate 2, Fig. 9, and differ in supporting one supraradial instead of two.” 
Even if this were true, which is not the case, it would have no specific sig- 
nificance, but would only indicate an abnormal condition of that specimen. 
By giving the specimen some additional cleaning, we disclosed two distichals 
in every ray, all supporting two extremely small palmars, as shown by our 
ficure (Plate LX XXIII, Fig. 9). The peculiarity that some of the inter- 
brachials are nine-sided, is caused by the distichals, which in three of the 
rays lean over to one side, so that one of them does not touch the interbrach- 
ials. In Miller and Dyer’s second type, Fig. 9a on the same plate, which 
we also reproduce (Plate LX XXIII., Fig. 8), the respective plates are all 
ten-sided. 
We must regard Lucalyptocrinus muralis Ringueberg as specifically iden- 
tical with Z. tuberculatus, until better specimens are found. Of Ringueberg’s 
type, which we had for comparison, only the dorsal cup is preserved, and this 
is so badly crushed as to give no idea of its actual form. It is quite possible 
that the base is somewhat broader than in Miller and Dyer’s types, that the 
plates generally are a little more convex, and the tubercles upon the plates 
somewhat less prominent, but the proportions of the plates are substantially 
the same. Similar variations may be expected in the limits of any species. 
