30 PROCEEDINGS OF THE ACADEMY OF 



Ecpachyckinus Boydii, M. and W. 



Body much depressed, or twice and a half as wide as high to the top of the 

 first radials, rounding inward above the second radials, and under to the very 

 profound central concavity below; composed of thick, strong, slightly convex 

 plates. Base very small, and deeply sunken in the concavity of the under 

 side. Subradials comparatively large, convex and curving upward above, and 

 under below, and then again upward into the concavity of the under side, 

 where each of them has a mesial indentation or notch ; each presenting a 

 general pentagonal outline, excepting two on the anal side, which are modi- 

 fied for the reception of the anal pieces. First radial pieces about twice as 

 high, convex, and equaling the subradials in breadth ; all pentagonal in form. 

 Second radial pieces convex, about half as large as the first, which they do not 

 quite equal in breadth, although they are in contact with each other laterally 

 all around, thus giving a contracted appearance to the body just above the 

 first radials ; each about twice as wide as high, pentagonal in form, and bear- 

 ing on one superior sloping side an arm, while on the other there rests a 

 smaller secondary radial bearing two arms ; thus making, as far as can be 

 seen, three arms to a ray, or if the same structure exists in all the rays, fifteen 

 to the entire series. First, or subanal, rather large, nearly quadrangular in 

 form, and resting between the sloping upper sides of two of the subradials, 

 under one side of the first radial on the right, and connecting with the second 

 radial on the left ; but apparently not always extending up far enough to have 

 its upper angle truncated by one of the succeeding anals above. Second anal 

 piece considerably smaller than the first, and resting upon the upper trun- 

 cated side of one of the subradials ; above these two or three smaller pieces 

 appear between the arms. Surface smooth. Sutures between the body-plates 

 rather deep. 



Arms slightly convex on the outer side, with lateral margins flattened and 

 straight, so as to fit closely together when raised up vertically ; each composed 

 below of a single range of wedge-fcrmed pieces, but soon passing into a double 

 alternating series above. 



Breadth of body across the middle, 0-90 inch ; do. across the second radials, 

 0-64 inch ; height to top of first radial pieces, 0-40 inch. 



This is a very neat, symmetrical crinoid, unlike any other known to us, and 

 remarkable for having its much depressed body rounding in above, at the top 

 of its first radial pieces, so as to be very distinctly narrower across above the 

 top of the first radials than below. Its sides also round very neatly under 

 below, and so far into the deep concavity of the under side that the lower 

 (inner) ends of the subradial pieces curve upward into the mesial concavity 

 nearly as far up as their outer or uppper ends. It seems to be the same form 

 figured by Prof. Yandell and Dr. Shuraard, in their " Contributions to the 

 Geology of Kentucky," (see fig. 4 a, b), without a description or name, from 

 near Grayson Springs, Kentucky. The specific name is given in honor of Dr. 

 Bovd, of Chicago, to whom we are indebted for the use of the last specimen 

 seen. 



Locality and position. Chester, Illinois. Chester division of the Lower Car- 

 boniferous limestone series. 



Homocrinus angustatus, M. and W". 



Bod\' below the first radial pieces more or less obconic, or somewhat con- 

 stricted below the middle. Base forming a narrow cup, sometimes nearly as 

 high as wide, with vertical sides ; composed of convex pieces, once and a half 

 to nearly twice as wide as high. Subradial pieces as long as the basals, or 

 sometimes a little longer, and always wider ; more or less convex, all hexa- 

 gonal excepting one on the anal side, which is heptagonal. First radial 

 pieces nearly one-third wider than high, being as wide as the subradials, but 

 shorter, and not so tumid ; all pentagonal, with the upper side truncated their 



[April, 



