20 
SMITHSONIAN INSTITUTION 
was an inference by Wachsmuth of a structure which had not actually been seen, based upon 
analogy of the Batocrinid genus Steganocrinus. It was criticised by Bather in his review of 
the Cainerata monograph, 6th notice, Geol. Mag., March, 1899, p. 125, calling attention to the 
fact that our interpretation had not yet received confirmation. 
This objection can now be met by the proved fact. Lampterocrinus is one of the best 
known and abundant crinoids in the Tennessee rocks, and from Roemer’s time on the calices 
were to be found in collections generally. They are firm, strong fossils, wdth thick plates 
solidly cemented together, well adapted to resist weathering in the glades. From these rotund 
bodies the other parts are readily detached, so that until now no one has ever seen any vestige 
of the arm structure. By the fortunate occurrence of some specimens intact in the Beech 
River shales, protected by the matrix which could be removed by preparation, we are now 
enabled to exhibit the complete crown wdth all the appendages in their natural position. In 
the remarkable series of specimens here studied, there are two with the tubular rays and side 
arms and the anal tube in place, and four others with parts of the radial extensions favorably 
located for inspection. There are five heavy tubes composed of the primibrachs and higher 
brachials curved like arm plates, wdth their covering plates, fringed wdth very long, slender 
arms given off alternately from each side, and bearing delicate pinnules — precisely the struc- 
ture of Steganocrinus sculptns of the Burlington limestone. The side-arms are uniserial, and 
each ossicle bears two pinnules, one from each side. 
While the type species remains as the chief representative of the genus, the new material 
has produced a well defined new one wdth a variant for a possible third. 
Hall described a small species L. parvus, from the Waldron shale, and also one from the 
Racine dolomite of the Chicago area, from which three species are also described by Weller. 
Rowley described another from the Missouri Silurian. None of these thrown any light on 
the structure. See Bassler’s Index for list wdth references. 
Lampterocrinus tennesseensis Roemer 
Plate 3, figs. 1-6 
Lampterocrinus tennesseensis Roemer. Sil. Fauna Westl. Tennessee, i860, p. 37, pi. 4, figs, i a, b. — 
Wachsmuth and Springer, N. A. Crin. Cam., 1897, p. 209.— Bassler, Bibliogr. Index, 1915, p. 690. 
This origdnal species, so well known in all collections by weathered speci- 
mens from the glades, is strongly characterized by its elongate form, sharp stel- 
late sculpture, and prominence of the anal interradiiis, which is larger than the 
others, and curves over into the tegmen where it passes into the strong sub- 
central tube, while the lower part is more or less swollen so as to produce a de- 
cided asymmetry. This anal “ hump ” is a most conspicuous character, by which 
the weathered calices are usually recognized at a glance. The sculpture takes 
the form of highly raised ridges passing from center to center of the plates, 
outlining a variety of triangles and hexagonal figures. At the anal side these 
often connect in such a way that they form a strong median ridge running the 
full length of the interradius from the posterior basal to the anal tube. 
The complete crown, free on both sides, was imbedded in a shaly limestone, where several 
instructive fragments of arms also occurred showing their mode of connection and relation 
to the tubular rays, and especially their bipinnulation, as in fig. 6. This peculiar structure, 
at one time considered to be an impossibility in crinoid morphology (Crin. Gotland, 1893, 
p. 36) , is now knowm to exist in several genera. I figure on plate 7 a specimen of Carpocrinus 
from Gotland in which the two pinnules to a brachial are well developed ; and the structure 
