m 



gle plate, and above this there are two small plates that unite 

 with the plates of the vault. The azygous area is a little larger 

 than a regular interradial area and the plates are larger, other- 

 wise it appears to be the same. 



The vault is convex, most tumid on the azygous side, and bears 

 a subcentral proboscis. The plates are large and most elongated 

 in the interradial areas. The proboscis is evidently nearly com- 

 plete in the specimen illustrated. It may have had another small 

 row of plates at the top surrounding the azygous orifice. There 

 are two elongated "ovarian apertures" with furrows prolonged 

 across the top of the calyx in each interradial area, and two sep- 

 arating the arms in each of the five rays, which gives to this 

 species twenty of these apertures. They are large and in striking 

 contrast with the small ones in Dolatocrinits corporosus, shown 

 in figure 2. 



This species is distinguished by its general form, surface orna- 

 mentation and sixteen arms. 



Found in the Hamilton Group at Charlestown, Indiana, and now 

 in the collection of J. F. Hammell at Madison, Indiana, in whose 

 honor we have proposed the specific name, and it is also in the 

 collection of Wm. F. E. Gurley. 



DOLATOCRINUS VASCULUM, n. sp. 



Plate V, Fig. 7, basal view; Fig. 8, summit view, part of the 

 vault broken away and showing the columuar canal 

 at the end of the basal plates; Fig. 9, 

 azygous side view. 



Species large. Calyx broadly truncated and concave below, the 

 concavity embracing .the first primary radials, and subcylindrical 

 above. Ml the plates are ventricose or subspinous and finely fur- 

 rowed, radiately toward the margins. The surface ornamentation 

 resembles that on Dolatocrinits amplus, but is more delicate, and 

 the nodes more pointed. 



Basals deeply sunken in the concavity and forming a pentag- 

 onal rim nearly twice as wide as the diameter of the column. 

 First primary radials wider than long and each having a trans- 

 verse obtuse node on the superior third. The two on the azygous 

 side are the larger. Second primary radials quadrangular, about 

 twice as wide as high and each bearing a transverse central node. 



