96 The American Geologist. August, 1902. 
Aristocrinus may have to give way to DactyJocrinus; 
1)oth seem to be founded on the same generic t}pe. 
Unless two of AngeHn's species, T. distcnsus and T. 
rigcns, are really without radianal, all the unsymmetrical Tax- 
ocrini belong to the Silurian. That is the case in America, 
where the form from New York and also that from Tennes- 
see, fall under Gnoriinocriiuis. 
The second family might perhaps be subdivided into two 
sub-families, embracing the sub-groups i and 2 as Sageno- 
crininae and Taxocrininae. 
The new genus Wachsuuitkicrinus mentioned in the fore- 
going table, is proposed in memory of my lamented colleague, 
Dr. Charles Wachsmuth, for the reception of certain species 
of Taxocrinidae which are distinguished by the absence of 
any anal plates. They hold somewhat the same relation to 
the family Taxocrinidae that IchtJiyocrinns docs to the Ichthy- 
ocrinidae, although, unlike that genus, they may possess in- 
terbrachials. The type is one of the best known species in 
the Lower Burlington limestone, always a favorite with the 
local collectors, described by Hall as Forbcsiocrinus thicinci 
(Bost. Jour. Nat. Hist.. MI, p. 317). 
The genus Parichthyocrinns is founded upon the species 
described by Wachsmuth and Springer as IchtJiyocrimis nobil- 
is (Proc. Acad. Nat. Sci. Phil., 1878, p. 254). Specimens 
since discovered show that it has a distinct anal side, with a 
vertical row of plates bordered by small irregular pieces con- 
necting it with the adjacent rays, as in Taxocrinus. It is an 
interesting intermediate form near IclUliyocrinus, having the 
abutting arms of that genus, combined with the anal side and 
interbrachials of Taxocrinus. 
The genus Oligocriuits is established for the reception of 
tlie form described bv Hall as Porbcsiocriiiiis asferiacfoniiis 
(Bost. Jour. Nat. Hist. \ II, p. 320), and hitherto referred 
to Onyc/wcriiiiis ; from which, as well as from all others of 
this group, it differs in having the ramules only on the out- 
side of the dichotom. It is the earliest of the Onyclwcrinus 
type, which later assumes an alternate mode of branching, 
first by short clusters and finall\" by ramules, simple or 
blanching, given off alternately from every second brachial. 
In this bilateral and alternate mode of branching mav be 
