266 TJie American Geologist. November, i89t) 
Two other radials do not bear the arms, or they support them 
in part only, and in that case also the arms must have been 
small. These posterior radials are much alike except in size. 
Fig. 2. Formula of Strophocrinus flicycliciis, showin? the relation 
of the radial plates. 
Between the right and left posterior radials are the azygous 
plates of w^hich three are pentagonal, a fourth is hexagonal, 
representing apparently two anchylosed pentagonal plates, and 
a fifth one^ — is constructed out of whole cloth, there being 
no such small quadrangular plate yet in the collection. The 
sixth azygous plate as usually designated, has already been 
counted as a basal. It is the large heptagonal plate on the left 
side (in figs, i and 2) of the small "posterior" basal, otherwise 
the "right" posterior basal ; and besides this there is a seventh 
representative in the smaller half of the pentagonal right pos- 
terior infrabasal. 
The type specimen has enough of one arm to show that it 
was comparatively slender and that if it branched at all, the 
l)ranching was not below the third brachial. Only the outer 
side of the arm is free from the matrix and what is known 
further of it has been learned only from isolated radials. These 
have a well defined articular area, bearing two cog-like ridges 
and a single medium groove, as figured, pi. xii, figs, i, 2, 3, 
and bearing also a raised horseshoe-shaped rim. Above the 
centre, of the articular area, as indicated by the converging 
processes, the radial plate is notched, and this notch is the only 
feature that marks also the inner side of the radials ; where it 
has a raised rim, fig. 4, pi. xii. 
The plates are often highly ornamented by abruptly ele- 
vated warts and these are either distributed or are arranged in 
rows or form ridges. This ornamentation builds a double 
svstem of rhomboidal areas the one around the angles of the 
