820 The American Naturalist. [ October, 
available data, and has made the type of Uintacrinus the subject of a 
a special morphological study. In this treatment the previous work is 
briefly referred to; but some of it receives criticism that it does not 
appear to deserve, particularly since the foundation of most of the 
adverse comments lies not in any material error in the work referred 
to, but in what is manifestly a clear misinterpretation or hasty perusal 
of that work. It is to certain of these points in the structure of the 
form that attention is directed in the present note. In making the 
correction, however, it is not with the idea of reflecting on Mr. Bather’s 
paper as a whole, for it is one of the most excellent contributions to 
echinoderm morphology that has yet appeared. The original figures in 
question from Bulletin 97 of the U. S. Geological Survey are herewith 
reproduced (Plate XV) in order to make more intelligible the exact 
points under consideration. 
In the memoir mentioned considerable space is occupied in criticising 
a recent account of the species; but most, if not all of the objections 
urged against Doctor Clark’s work, are certainly more imaginary than 
real. Professor Clark’s figures come in for special condemnation as 
violating the fundamental law of the alternation of the pinnules. Asa 
matter of fact his plate which is reproduced in the Proceedings as Plate 
LVI, to point out the alleged errors, not only shows that the accom- 
panying statements are not true, but that in all three figures there is 
strict alternation of the pinnules in every case. 
The general law in the pinnulation of the genus Mr. Bather states as 
follows: IIBr, none, I1Br, outer, IIBr, none, I1Br, inner, IIBr, outer, 
IIBr, none, II Br, inner, IIBr, outer, IIBr, none. Two of bis ten speci- 
mens differed from this general rule: one showing IIBr, inner, IIBr, 
none, II Br, outer, IIBr, inner ; and the other IIBr,; none, IIBr, outer, 
ITB, inner, IIBr, none, IIBr, outer. He makes out the formula for the 
Clark figure la to be IIBr, outer, IIBr, none, IIBr, outer. The real 
formula for this is IIBr, outer, IIBr, inner, IIBr, outer, IIBr, inner, 
IIBr, outer. This appears clearly indicated in the figure, and Mr. 
Bather’s statements that IIBr, has no pinnule is certainly a typograph- 
ical error, for it cannot be that he mistook the rough, broken and highly 
raised edge of the brachial row of plates, with its deep shadow, for a 
suture line connecting with the first inside pinnule. The figure is of 
a somewhat crushed and distorted specimen, and the perspective is, 
perhaps, not as good as it might be. Whether or not it is the same as 
that figured by Meek (Bather’s figure 2) is not known ; but if the two 
are the same, the difference in the sketches are not very great nor 
radical, and certainly not as contradictory as Mr. Bather would have 
