396 THE CRINOIDEA CAMEEATA OF NORTH AMERICA. 



side, where the anal plate is followed by three and two pieces. Ventral disk 

 higher than the dorsal cup, distinctly bulging at the anterior side, and hence 

 shorter at the posterior. The plates flat and smooth, except the posterior 

 oral which is sometimes slightly convex, and is strictly central in position. 

 The ventral tube is excentric, bending obliquely upwards, so as to pass out 

 frequently from between the arms. It is composed of thick, tumid pieces, 

 heavy throughout, stoutest at midway, and obtusely pointed at the upper 

 end, where there is a small aperture. Column small, the upper joint occu- 

 pying but one third the width of the basal disk. 



Horizon and Localittj. — Upper Burlington limestone; Burlington, Iowa, 

 Henderson Co., Ills., and Sedalia, Mo. 



Types in the (Worthen) Illinois State collection, and in the Museum of 

 Comparative Zoology. 



Remarks. — This species is readily distinguished by the bulging and 

 asymmetrical form of the ventral disk, the stout, inflated and curving anal 

 tube, and by the form of the arms, which widen more gradually than in 

 any of the preceding species. 



Eretmocrinus calyculoides, var. nodosus W. and Sp. (nov. var.). 

 PMe XXXIV. Figs. 6, 7, 8. 



The specimens for which we propose this variety differ from Eretmocrimis 

 calyculoides in having transverse angular nodes on all radial plates, and 

 rounded nodes upon the interradial ones. Its general form is somewhat 

 more elongate, less spreading near the arm bases, the radials are propor- 

 tionally smaller, the ventral disk less bulging ; it generally has twenty arms, 

 and these do not attain the same width in the flattened portions. In all 

 other respects it agrees with the typical form. 



Horizon and Locality. — Upper Burlington limestone; Pleasant Grove, Iowa. 



Types in the collection of Wachsmuth and Springer. 



Eretmocrinus matuta (Hall). 

 Plate XXXVII. Figs. 6a, I, c. 



1861. Adiaocrinus matuta — Hall; Prelim. Descr. New Spec. Crin., p. 14. 



1873. Batocrimis (^Eretmocrimis) matuta — Meek and Worthen ; Geol Hep. Ulinois, Vol. V. , p. 368. 



1881. Eretmocrinus matuta — W. aud Sp. ; Revision Paleeocr., Part II., p. 173. 



Calyx small, subclavate, longer than wide. Dorsal cup once and a half 

 as high as the ventral disk, expanding but little from the top of the basals 



