HETEROCRINIDAE 
87 
Myelodactylus extensus Springer 
Plate 2^, figs. 11-18 
Springer, Unusual Forms, 1926, p. 14, pi. 3, figs. 1-13. 
Like animonis, except that the coil is open beyond the proximal region, 
and stem extended for a considerable distance in a broad curve toward the dis- 
tal end. 
Beech River formation; Decatur County, Tennessee. 
Myelodactylus brachiatus Hall 
Plate 2y, fig, ip 
Myelodactylus brachiatus Hall, Pal. New York, 2, 1852, p. 232, pi. 45, figs. 7 a-e. — Springer, Unusual Forms, 
1926, p. 14, pi. 4, figs. i-io. 
Coil Open, circular part of stem very long and slender, with crown tending 
to be free of the coil ; cirri limited to the distal end, few, long, branching, and 
alternating at intervals of several columnals. 
Rochester shale; Lockport, New York. 
Myelodactylus keyserensis Springer 
Plate 2J, figs. 20, 20a 
Springer, Unusual Forms, 1926, p. 19, pi. 6, figs. 1-3. 
Coil open; cirri numerous, long, slender, paired on successive columnals; 
crown large, with long arms branching repeatedly, swelling between the two 
rows of closely packed cirri ; rays 5, of locrinus type. 
Keyser formation, Helderbergian ; Lower Devonian ; Keyser, West Virginia. 
Myelodactylus schucherti Springer 
Plate 2J, fig. 21 
Springer, Unusual Forms, 1926, p. 21, pi. 5, figs. 9-90 
Coil close, circular part of stem thick and long; cirri round, short, paired 
on successive columnals. 
Linden formation, Helderbergian, Lower Devonian; Benton County, Tennessee. 
Myelodactylus nodosarius (Hall) 
Plate 2^, figs. 22-24 
Brachiacrinus nodosarius Hall, Pal. New York, 3, 1859, p. 118, pi. 5, figs. 5-7; pi. 6, figs. 1-3.— Goldring, 
Devon. Crin. New York, 1923, p. 332, pi. 41, figs. 1-4. — Herpetocrinus nodosarius Bather, Amer. GeoL, 
16, 189s, p. 213. — Myelodactylus nodosarius Springer, Unusual Forms, 1926, p. 20, pi. 5, figs. 1-8. 
Coil open ; stem elongate, terminating in a bulbous enlargement ; cirri few, 
short, thicker than the stem and thickest in the middle, alternating at intervals 
of I to 5 columnals, composed of a few rounded, bead-like cirrals. 
New Scotland formation, Helderbergian, Lower Devonian ; Schoharie County, New York. 
