PLATYCRINIDAE 
49 
stood, partly owing to scarcity of material, and partly to the inherent obscurity of all the 
early Platycrinidae because the dorsal cup is so simple and alike in so many genera. It has 
been shifted about in classification ; but most of the later authorities agree in placing it among 
the Platycrinidae along with Culicocrinus. From this Jaekel in his work on Phylogenie und 
System, 1918, dissents, and while placing Culicocrinus among the Platycrinidae greatly re- 
stricted, transfers Coccocrinus to an entirely different order, and ranks it in a suborder 
Hyocrinites along with Mesozoic and Recent forms such as Eudcsicrinus, Hyocrinus, Ptilo- 
crinus, etc. 
The typical species, C. rosaceus, described by Roemer in 1844 as Platycrinus, was made 
by Johannes Muller the type of Coccocrinus in 1855. It has a tegmen constructed mainly of 
five large triangular plates, interlocking and forming a pyramid somewhat resembling that 
of Haplocrinus, having grooA'^es along their edges ; but with this difference, that whereas in 
Haplocrinus the ventral pyramid rests directly iipon the shoulders of the radials, in Coccocrinus 
there is a set of plates interposed called “ suborals,” interbrachial in position, on which the 
triangular plates rest in direct succession. The anus is at the line of junction between the 
posterior interbrachial and the triangular plate, each being notched for the opening. The 
structure is well shown by figures i and 2 on plate ii, the first being from what is probably 
the original of Schultze’s figure in his monograph of the Eifel Echinoderms, and the last 
from the specimen figured by Wachsmuth and Springer in the Camerata monograph, pi. 3. 
fig. 14, obtained by me at Gerolstein in 1887. There is a slight difference in the contour of 
the tegmen of the two specimens, and in the appearance of the grooves, partly due to differ- 
ence in preservation — the last being somewhat crushed — but the essentials are the same. It 
is a Middle Devonian species. 
The nearest allied form to Coccocrinus is Culicocrinus, described by Johannes Muller 
from the Lower Devonian, which has likewise a tegmen composed of 5 large orals,. but they 
are closely united by suture, without any groove along their edges ; they are also preceded by 
plates interbrachial in position (pi. ii, figs. 3, 3a, 4, 4a, h, c). The chief difference between 
the tw’o genera, so far as can be ascertained from the material available, is said to be that 
Culicocrinus has heavy, biserial arms, while in Coccocrinus, the arms are supposed to be uni- 
serial and rather delicate, and that the former has the lower brachials more deeply incor- 
porated in the cup than the latter. 
The tegmen of Culicocrinus is paralleled by that of Myrtillocrinus Hall, from the Onon- 
daga of New York, in being composed of closely interlocking oral plates, but without any 
underlying interbrachial structures (pi. ii, figs. 5, 5a). 
In i860 E. Roemer described the species Coccocrinus hacca, from the Silurian of Ten- 
nessee. It was a rare form, and he had but few specimens, which disclosed nothing of the 
tegmen ; but he saw the beginning of the interambulacral plates, which he and subsequent 
authors took to be the “ suborals ” as in C. rosaceus. Little addition to his knowledge was 
obtained by later collectors, Wachsmuth in his Tennessee excursions finding but four speci- 
mens, one of which preserved some of those plates, but not intact. This was figured in the 
Camerata monograph, pi. 75, figs. 1 5a-c. It has been assumed that the interbrachially situated 
plates here, as in Coccocrinus, Avere followed by a pyramid of triangular plates substantially 
covering the ventral side. Much of the discussions of the generic position of Coccocrinus 
hitherto has been based on this species, now here separated. 
Among the collections made for me in Tennessee in 1906-7 is an extraordinary lot of 
material of this species from which considerable new information has been derived. There 
are in all about 1,000 specimens, from two colonies not far apart. They occurred mostly in 
a shaly and limestone deposit disintegrating into clay, forming part of the lower member of 
the Beech River formation designated by Pate and Bassler as the Coccocrinus zone. The 
specimens chiefly consisted of the calyx only, but a few were found with more or less of the 
arms attached, uniserial, and ten in number. Many of the specimens have the interambulacral 
