HETEROCRINIDAE 
II3 
that genus, while the structure of the lateral arms is substantially that of Euchcirocrinus, 
with a difiference, however, in the proportionate size of the branches. The specimen figured is 
unique, and only the left posterior side is fully exposed ; but I was al)le to free the opposite 
side sufficiently to show that it has but one lateral arm. It is an intermediate form of uncertain 
position. 
Horizon and locality. Eucalyptocrinus zone of Beech River formation, Brownsport 
group, Niagaran; Tuck’s Mill, Decatur County, Tennessee. 
Euchcirocrinus Ontario Springer 
Text- fig. 3b 
Eucheirocrimis Ontario Springer, Geol. Surv. Canada, Mem. 3, No. 91, 1919, p. 127, fig. 6. 
This species, described by me some years ago, is of somewhat earlier age than the type ; 
it is inserted for comparison of arm structure, especially of the median arm, which bifurcates 
on the third brachial, and the branches at least once more at like intervals beyond. This 
an-angement is shown l>y text-figure 3& under E. chrysalis. From the Cataract formation, 
Medinan ; Stony Creek, Ontario, Canada. 
Euchcirocrinus anglicus new species 
Plate 2g, figs. 6, 6a; text-fig. 3c 
This small species from the English Silurian is described here on account 
of the extraordinary variation from the type which it exhibits in the branching 
of the median arm. This bifurcates on the first and only primibrach, and then 
once or twice more to the number of at least 6 ultimate branches; the lateral 
arms are irregular, both their rami and their branches being of an intermediate 
character (text-fig. 3c). The branching of the median arm on the primibrach 
is paralleled only by the species Calceocrimis pinnulatus Bather (Grin. Goth, 
pi. 4, fig. 133) of Gotland; but whereas in that species the lateral arms have the 
usual two primibrachs, here the single axillary primibrach extends to the lateral 
arms also, thus duplicating the otherwise unique character of another Gotland 
species, C. nitidns, which occurs also in England in the same formation and 
locality as the present species. In the profuse branching of the median arm 
this species recalls a similar departure from type in Calceocrimis hiftircatiis. 
The species is based upon a single specimen, unique so far as I know, from Dudley, 
England, which I obtained many years ago from the well known dealer, Robert Damon of 
Weymouth. It is notable for the rather ponderous character of the arm branches, the great 
predominance of the median arm, and the relatively small size of the calyx. It has a short 
stem, apparently about half the length of the crown, which seemed to end amid the debris 
of some other fossils so that it could not be determined whether the stem was attached to a 
foreign object or not. The columnals increase in length rapidly toward the distal end, where 
they become twice as long as wide. In this respect the form has a rather juvenile aspect. The 
crown, which is considerably flattened by pressure, has a height of 20 mm. 
Horizon and locality. Wenlockian, Silurian ; Dudley, England. 
