ART. 3. TERTIARY CRi:NrOID FROM WEST INDIES SPRINGER. 7 



pentagons and centrodorsals of comatulids. Such remains have ac- 

 tiiallj been found at Newcastle, New South Wales, Singapore, Ta- 

 ranto, and on the coast of Kent in England. 



Not far below the surface in a few widely separated localities 

 live large pentacrinites, Holopus^ and Democrlnus. 



The crowns of the pentacrinites are almost as fragile as the coma- 

 tulids, and very soon go to pieces, while the arms of Democrinus are 

 extremely fragile, and the column is rather brittle. 



Since Dr. W. B. Carpenter reported that once after a hurricane 

 the beach at Barbados was strewn with pentacrinites of all sizes, 

 and 7 of the 11 known specimens of Holopus rangii were found on 

 the beach (6 of them at Barbados), and the first known species of 

 Democrinus was described from a. recent breccia at Guadeloupe con- 

 taining a human skeleton, it follows that a recent reef if fossil might 

 contain fragments of pentacrinite stems, fragments of Democrimis 

 stems, or well-preserved specimens of Holojms. 



As the foregoing sketch gives a fairly complete survey of what 

 M'e might expect if the present reefs and beaches were known only 

 as fossil strata, we may hazard the assumption that the scarcity of 

 crinoids in the Tertiary means nothing more nor less than that at 

 that time the crinoids first began to exist chiefly under the conditions 

 delimiting their occurrence at the present time. 



Horizon and locality. — Artibonite formation, lower Miocene, Ter- 

 tiary. Divide on trail between La Chapelle and Mirebalais. Re- 

 public of Haiti. Collected by J. S. Brown, December 18, 1920. 

 U. S. Geological Survey loc. No. 9494. 



Tijpe.—ln U. S. National Museum, Cat. No. 352556. 



EXPLANATION OF PLATE. 



All figures are enlarged about two diameters. 



Balanocrinus haitiensis new species. 



Lower Miocene. Island of Haiti. 



Fig. 1. Tlie longest stem-frugment, about 41 mm., witb a longitudinal row of 

 irregular pits along the radial line due to erosion or chemical action. 



Figs. 2, 3. Specimens showing distortion of the stem produced by crushing, 

 the first having probably a cirrus-facet preserved. 



Figs. 4, 4a. Two views of a stem-fragment with the convex edge of some petals 

 exposed by erosion at the side and top, and at the latter the remnant of what 

 is probably the normal joint-face with the radial ridges much eroded, leav- 

 ing petal floors rounded and prominent ; only faint traces of crenulae remain. 



Figs. 5, 5a. Side and terminal views of a stem-fragment with sides eroded 

 along longitudinal radial lines, leaving the interradial sectors convex ; the 

 upper face being possibly a syzygial joint, with obscure traces of cirrus- 

 facets, the radial ridges rounded and their bordering furrows distinctly out- 

 lined ; some peculiar striae are seen in two of the petal areas. 



