160 PROCEEDINGS OF THE ACADEMY OF 



Height of body to horizon of arm openings, 0-70 inch ; breadth at same, 1-60 

 inches. 



This species resembles in the sculpturing of its body plates S. fflt/ptui, Hall 

 (sp.), but has a more depressed body, and is also at once distinguished by 

 having a proboscis, while the S. glyplus belongs to the section of the genus 

 with merely a simple opening in the vault. From S. xgilops it will readily be 

 distinguished by its shorter, more rapidly expanding body and less numerous 

 arms, as well as by its different sculpturing. Although its brachial pieces 

 are a little separated over the anal, interradial, and axillary spaces, there are 

 no distinct sinuses at these points in the margins of the disc, as the little 

 intercalated pieces separating the brachial pieces at these places extend out 

 as far as the latter, so th\t when the arms are removed the outline of the disc 

 presents only an obscurely subpeutagonal outline. 



Locality and position. Lower division Burlington beds of Lower Carbonif- 

 erous, at Burlington, Iowa. No. 59 of Mr. Wachsmuth's collection. 



Strotocrinus ? ASPERRiMus, M. and W. 



Body under medium size, urn-shaped, being a little wider at the top 

 of the third radials than high, with the secondary radials and succeeding 

 parts spreading out horizontally, but divided by narrow anal and interradial 

 sinuses quite in to the body ; sides ascending with a gradual expansion to the 

 top of the third radials, with a moderately convex outline below the middle. 

 Base about twice and a half as wide as high, not thickened or spreading 

 below, but projecting downward a little around the column, in the form of 

 little nodes, formed by deep notches at the sutures and smaller ones between. 

 First radials generally wider than long. Second radial pieces somewhat 

 smaller than the first, wider than long, some hexagonal and others pentago- 

 nal. Third radials a little smaller than the second, generally pentagonal and 

 bearing on each superior sloping side a secondary radial, each of which sup- 

 ports one or more brachial pieces, leading to an arm on its outer sloping 

 side and a small tertiary radial on its inner, each of which evidently sup- 

 ported two other pieces above, one or both of which were probably brachi- 

 als. If both sides bore brachials it would make six arms to the ray, but if 

 one side bore an axillary piece it would make eight to the ray or forty in the 

 whole series. 



First anal piece of about the same size as the smaller first radials, slightly 

 longer than wide, hexagonal in form, and succeeded by two smaller hexago- 

 nal or heptagonal pieces in the second range, above which there seems to be 

 about four other smaller pieces Subradials three or four to an area, the 

 first one about as large as the second radials, hexagonal or heptagonal in 

 form, and supporting two smaller pieces in the next range ; above this there 

 seems to be one, or possibly sometimes two other smaller pieces. Axillary 

 spaces sometimes occupied by one or two small pieces. 



Vault much depressed, or rising little above the horizon of the arms, com- 

 posed of irregular small and moderate sized pieces, and provided with a 

 nearly central proboscis, which in the typical specimen is composed of very 

 small pieces at the base, and a little inclined to one side. 



Surface of body plates all prominent and angular in the middle, and pro- 

 vided with well defined, sharp radiating costse, which are compound on the 

 first radial and first anal pieces, but generally consist of a single rib, extend- 

 inf from the middle to each of the sides of the others. The mesial promi- 

 nence on each of the first and second radials is pinched out so as to form a 

 prominent sharp, transversely arranged ridge, while on each of the smaller 

 plates it is a rounded, rather pointed node, the whole presenting a very rough 

 appearance. 



Height of body ta the horizon of the arms, 0-74 inch ; do. to top of vault, 

 0-88 inch ; greatest breadth at the top of third radials, 0-80 inch. 



In general form and surface markings this species resembles the following, 



[July, 



