BATOCRINID^. - 453 



Macrocrinus lagunculus (Hall). 

 Plate XXXV. Fig. 4. 



I860. Acdnocrinus lagunculus — Hall j Suppl. Geo!. Rep. Iowa, p. 41. 



1867. Batocrinus lagunculus — 'i£. andW. ; Geol. Rep. lUiuois, Vol. V., p. 367. 



1881. Batocrinus lagunculus — W. and Sp. ; Revision PalEeocr., Part II., p. 166. 



A very small species of the type of Macrocrinus verneuilianus, but the 

 dorsal cup proportionally longer, and the arm openings formed into an 

 almost continuous ring around the calyx. Calyx once and a half as high 

 as wide. Dorsal cup conical, as high as the width at the arm bases ; the 

 sides a little convex. Surface of plates slightly elevated, and beveled at the 

 margins. 



Basals moderately short, thickened at their lower margins, and forming a 

 rim, which is not indented at the sutures. Radials longer than wide, the 

 superior faces concave. First costals twice as wide as long, quadrangular ; 

 second costals pentagonal, exceptionally hexagonal in the postero-lateral 

 rays. The anterior ray has 3X2 distichals and two arms ; the antero- 

 lateral but one distichal and four arms ; while the two postero-lateral 

 ones, which sustain three arms, have toward the anal side a distichal and 

 two palmars, and at the opposite side three distichals, making sixteen arms 

 to the entire species. First anal plate as large as the radials, slightly longer 

 but narrower ; the second anal a little larger than the two interbrachials 

 aside of it. The next row consists of two or three pieces. The four regular 

 sides contain three plates, which are arched by the arm-bearing brachials, 

 and also those of the posterior side. Tegmen conical, gradually passing into 

 the anal tube, which is very stout ; plates nodose, decreasing in size as they 

 approach the arm-bases. Orals excentric ; the posterior one standing erect, 

 to one side of the anal tube. 



Horison and Locality. — Keokuk group; Warsaw, Ills., and Keokuk, 

 Iowa. 



T//2}e in the Illinois State collection, Springfield. 



