C A L Y PTO C R 1 N J D AE 
35 
Family CALYPTOCRTNIDAE Ang-elin 
i\fonocyclic. Dorsal cup usually with 4 BB and concave base ; lower brach- 
ials and interbracbials incorporated in cup, which above the base is perfectly 
pentamerous; plates of calyx usually limited to a definite number; radials in 
contact all around ; no anals ; arms, usually 20, resting in pairs in compartments 
formed by vertical partitions borne by processes rising from the fixed iBr and 
iTIBr to varying heights; tegmen elevated in a central anal tube, and composed 
of 4 circlets of large plates variously shaped bearing the partitions. Silurian 
and Devonian. 
For instructive diagrams illustrating the structure, see N. A. Crin. Cam., 1897, p. 331. 
EUCALYPTOCRINUS Goldfuss 
Plates 7, 8 , p 
EucaJyt'tocrinites Goldfuss, Petref. Germ., 1826, p. 214. 
Eucalypfocrinus, Agassiz, Ann. Nat. Hist, 1838, p. 447. — Wachsmiith and Springer, Rev. Pal, 3, 1885, 
p. 127; N. A. Crin. Cam., 1897, p. 332. — Bather, Treatise on Zool., 3, igco, p. 164. — 'Weller, Bull. 
Chicago Acad. Sci., 4, pt i, 1900, p. 102. — Zittel-Eastman, Textb. Pal., 2d ed., 1913, p. 192. — ^Jaekel, 
Phylogenie und System, 1918, p. 32. — -Complete reference with list of synonyms and species, Bassler, 
Bibliogr. Index, 1915, pp. 501-507. 
Calyx elongate to wide spreading; BB 4, at bottom of an inverted funnel 
formed by RR at the sides, followed by IBr, IIBr and IIIBr, 2 each; iBr one 
large 8- or lo-sided, angular above, supporting a pair of elongate plates of 
second range extending upward between the arm-bases to a connection with 
the partitions; a single ilTBr of similar form rests upon the truncate second 
IBr and connects with the partition in line with the ray. No anals. Arms 
biserial, paired, resting in to vertical compartments bounded by partitions sup- 
ported by processes arising from the iBr and illBr plates extending the full 
height of the tegmen and meeting above in a circlet of peripheral plates. Tegmen 
composed usually of 4 ranges of plates, tubular, expanding upward into a 
canopy having an inner set of plates variable in number, often 4, surrounding 
a central anal opening, either direct, or produced into a short tube. 
Genotype. Eucalyptocriniis rosacens Goldfuss. 
Distribution. Silurian; Gotland, England, America. One species in Middle Devonian, 
Germany. 
This prolific Silurian genus, first described from a Devonian species, which still remains 
the only one known from that epoch, has by the growth of research become the leading known 
crinoid of its typical horizon, both in variety and distribution. Some 40 species have now 
been described from the European and American areas, including 7 from Gotland, 3 from 
England, and 30 from the Niagaran of America, some of which are probably synonyms. 
The American species are distributed among the subdivisions of the Niagaran as follows ; 
Rochester 4, Waldron 7, Racine 9, Beech River 8. Decatur 2. The last 2 are now first de- 
scribed, one of them marking a new departure from the type. The Tennessee collections 
