22 



DOLAT0CRIND8 BULBACEUS 11. Sp. 



Plate II, Fig. 13, based vieiv; Fig. 11, summit view: Fig. 15, side 



view. 



Calyx and vault together bulbous. Calyx pentagonal from base 

 to the arms, somewhat bowl- shaped, most expanded in the middle 

 part, slightly constricted below the arms; columnar cavity deep. 

 Surface marked by strong radial ridges, and a prominent node in 

 the central part ol each first iuterradial from which radiating ridges 

 extend to the adjoining plates. 



Basal plates almost hidden by the column though extending a 

 little beyond it. First primary radials about as long as wide and 

 abruptly bent in the middle, the lower part forming part of the 

 funnel-shaped columnar cavity andthe upper end curving as abruptly 

 upward. In the center of each there is a prominent node, from 

 which the radial ridges arise, and which are connected by straight 

 ridges, from one to the other, that form the pentagonal outline of 

 the base, and on which the calyx will rest, if placed on a level 

 surface. Second radials quadrangular, very little wider than high 

 and sides nearly or quite parallel. Third primary radials about 

 twice as wide as high, expanding from below to the lateral angles> 

 pentagonal and supporting upon each of the superior sides two 

 short, secondary radials. 



The first secondary radial is much larger and wider than the 

 second and abuts one side against a truncated corner of a first in- 

 terradial and another against the secondary interradial. The sec- 

 ond secondary radials abut against each other, are rounded extern- 

 ally and assume the form of the arms. The arms in each radial 

 series are thus arranged close together, and the arm openings are 

 directed upward. There are only ten arms, and they consist, as 

 we infer from the commencement, of a single series of plates. 



The first interradials are the larger plates of the body and have 

 nine sides. Tiiey are convex centrally and have a prominent cen- 

 tral node from which ridges radiate to adjoining plates. The sec- 

 ond interradials are about half as large as the first, bear a central 

 tubercle, aic iicplngonal, abut laterally upon the first secondary 

 radials, and a smfdl plate that separates the first and secondary 

 radials from the plates of the vault and forms part of the base of 

 the arms, and the two superior sides abut two interradial plates 

 belonging to the vault. 



