44G 



REMARKS ON NEW SPECIES OF CRINOIDEA, 



gradually rose from the arm-bases about half of the height of the dome; then, more 

 rapidly, about one -third of the height, when the curve of elevation was gradually reversed, 

 and the summit of the dome rounded into a form sub-hemispherical. 



The cicatrices, showing the location of the arms, form a closed zone around the calyx at 

 the point of its greatest diameter. In this arrangement of the arms, it resembles Boto- 

 crinus. Below the arms, the calyx is depressed vasiform; the base deeply excavate for the 

 reception of the column, which covers and completely conceals the basal pieces. These 

 are not visible from the outside of the specimens, even in the absence of the column. 



Basal pieces three in number ; when detached from the body present a shallow cup ; the 

 interior surface is rounded by the considerable thickness of the pieces, having five angular 

 points, and five concave depressions between them; the spaces which cross the junction 

 of the pieces with each other, being deeper than those upon the ends of the two large 

 basal pieces. The centre of the base has a deep hemispherical depression around, and 

 including the opening between the body and the column; the parts of the basals around 

 this opening are quite thin ; the main body of them are remarkable for their thickness. 

 Well-preserved specimens arc marked with a leaf-like depression, which originate around 

 the opening, and extend toward, and terminate near the five points of the margin of the 

 base. First radiala; five in number. Compared with the other pieces forming the body, 

 they are very large, resting on the basals, and extend downward and outward ; joined to 

 each other and the base, they form a deep cup. They vary in size, and differ in form : 

 three are hexagonal, the two largest pieces are sub-septagonal — having two angular prom- 

 inences on the summit of each — the other three are squarely truncated at their superior 

 extremity. The second radials, of the first series, arc comparatively small. These rest 

 against the square ends of the three smaller first radials, and in the notched space at the 

 summits of the two irregular first radials ; they are pentangular, cuneiform, and support, 

 each, two radials of the second series. The second piece of the radials of the second series 

 is also cuneiform, and support each two radials of the third series. The rays are again 

 divided on the second radial of the fourth series. There arc other divisions of the radials ; 

 these are not sufficiently marked for description. Our specimen probably had eighty 

 rays. It is not improbable that the number of free rays increased with the growth of the 

 animal. Some fragments evidently of the same species as this under consideration, show 

 distinctly the fourth division of the radials upon the body and below the free rays. If the 

 rays bear an equal number of free arms, on the fourth division there would be 5x2=10 

 x2=20x 2=40x2=80x2=160* 



* Pig. G2, pi. xxvi, was taken from a specimen in the collection of Dr. L. P. Yandell, who, for the pur- 

 poses of this description, has kindly placed his cabinet at my disposal. 



This specimen is figured to show the arrangement and proximity of the arm-bases. If the curve 



