14 



his illustrations, and which are quite conspicuous in our speci- 

 mens. These pores or passages are elongated. They commence 

 by a slight horizontal furrow across the top of the last interradial 

 plates in the calyx and penetrate the adjoining plates of the vault 

 horizontally, which makes an elongated surface opening. This 

 feature is present and even more noticeable in Dolatocrinus grandis 

 and may be understood by referring to the illustration of that 

 species. We know all these openings penetrate the test because 

 we can see through them. 



This species occurs in the Upper Helderburg Group, at the 

 Falls of the Ohio, and in Clark county, Indiana. 



DOLATOCRINUS GRANDIS, n. sp. 



Plate II, Fig. 1, basal view of the calyx; Fig. 2, view of the 

 vault broken in the central part; Fig. 3, lateral view. 



Calyx very large, subhemispheroidal, quite concave below, the 

 concavity including part of the third primary plates, and most de- 

 pressed in the interradial areas. The diameter of the specimen 

 illustrated is two and three tenths inches; height to the place 

 where the vault is broken, one and fifty-five hundredths inches; 

 height of calyx, nine- tenths of an inch; height of vault, if un- 

 broken, and calyx about equal. The vault is quite convex, a little 

 more abrupt on one side than the other, indicating that it pos- 

 sessed a proboscis on the abrupt side, and it is very slightly de- 

 pressed Jn the interradial areas. Surface of the calyx beautifully 

 and delicately sculptured, numerous raised lines seem to cross the 

 sutures from one plate to another, but none of them arise from 

 nodes or tubercles. The sutures are not beveled and in some parts 

 they are very indistinct. The sutures on the vault are dis- 

 tinct and beveled and between the larger plates they are broadly 

 and, deeply grooved, the grooves being bounded with a rim of 

 granules, while the central part of each plate is concave or sculp- 

 tured and sometimes granulous. The columnar cavity and part of 

 the first primary radials, in our specimen, are covered with the 

 limestone matrix. 



First primary radials very little wider than high, upper side 

 transverse. Second primary radials quadrangular and about one- 

 fourth wider than high. Third primary radials larger than the 

 second, pentagonal, and from one-fourth to one-third wider than 



