122 
SMITHSONIAN INSTITUTION 
Halysiocrinus marylandensis (Ohern) 
Plate 2Q, figs. 2g, 2ga, b 
Calceocrinus marylandensis Ohern, Maryland Geological Survey, Lower Devonian, 1913, p. 253. pi. 40, 
figs. 1-3. 
This species, described for the Maryland Geological Survey, is figured here 
to show the occurrence of the genus in the Oriskany division of the Lower De- 
vonian. It is remarkable for its robust proportions in contrast to the other 
Devonian forms, but the generic characters are thoroughly well established. 
There are at least six axil-arms springing from extremely unequal-faced main- 
axils, and the main arm-branches are fairly well exposed alongside the large 
outer ramules. The median arm is simple to the eleventh brachial, and of un- 
usual size, as are also the plates of the anal series. The whole aspect of the 
crinoid is one of massiveness not before observed in the family. 
Only the type specimen is known, from the Oriskany sandstone at Cumberland, Maryland. 
Halysiocrinus carinatus new species 
Plate 2g, figs. 24, 24a, 25, 26 
This Hamilton species is introduced in order further to show the course 
of development of the family during- the Devonian, and especially as a fine ex- 
ample of the indentation of the large anal plates by pressure on the stem. It is 
remarkable for the extraordinary number of axil-arms, lo on each side, the 
narrowness of the 1. ant. superradial, and slenderness of the median arm follow- 
ing it, of which only a few brachials are preserved ; this is very small and keeled, 
in contrast to the broad, rounded arm of most other species. The space gained 
by the reduction in width of this arm affords room for the increased number of 
main-axils, as a result of which the lateral arm-facets are directed more nearly 
upward than in other species ; this character is constant in specimens from the 
three localities. The axil-arms are also slender, with elongate brachials in two 
or more well exposed branches. The anal plates are very large, and the inden- 
tation made by the stem is sharp and deep, and could only have been produced 
by strong and persistent pressure, such as would result from a habitual recum- 
bent position of the crown upon the stem. No mere temporary suspension of the 
crown alongside the stem would account for it. The anal tube is sharply angu- 
lar, tapering to a point below the distal end of the arms ; this form of tube is 
a striking character of the species which has not been seen in any other, and 
reminds one of the pointed tube in some species of Zeacrinus, leaving the posi- 
tion of the anal opening in doubt. Surface of radials and basals corrugated or 
pustulose. 
The species is founded on two crowns from the Traverse formation of northern Michi- 
gan ; the type here figured, 38 mm. in height, is sharply and accurately preserved, except for 
