14 



ACTINOCR1NTJS ERRATICUS, n. Sp. 



Plate II, Fig. 2, view opposite the azygous side; Fig. 3, azygous 



view. 



Body medium size. Calyx very little larger than the dome, 

 somewhat obpyramidal, the radial series being slightly more 

 prominent than the interradiais, diameter one-half greater than 

 the height; plates thick, tumid and sculptured. Dome elevated 

 at the arm openings, subpyramidal, being most prominent in 

 the direction of the radical series and covered with tumid and 

 spinous plates. Proboscis central. 



Basals short, more than three times as wide as high, project- 

 ing beyond the column, in the form of a small rim, separated 

 at the sutures, so as to have a somewhat hexagonal outline; 

 sculptured longitudinally, so as to show a short ridge directed 

 toward each adjoining plate. 



First primary radials the larger plates of the body, nearly as 

 long as wide, very tumid transversely and having a short ridge 

 directed toward each adjoining plate. Second primary radials 

 a little smaller than the first, wider than long, transversely 

 tumid and having a short ridge directed toward each adjoining 

 plate. Third primary radials about as large as the second, 

 much wider than high, transversely tumid, having radial ridges, 

 and bearing upon each upper sloping side a single secondary 

 radial, which, in turn, supports upon each upper sloping side 

 two tertiary radials. There are twenty arm openings to the 

 vault. 



First regular interradiais of the same size as the second pri- 

 mary radials; each one bears a strong central tubercle with a 

 radiating ridge directed toward each adjoining plate; it is fol- 

 lowed by two smaller plates, each of which bears a central 

 tubercle; these are followed by two still smaller plates, each 

 bearing a central tubercle, and these are followed by a single 

 non-tuberculated plate within the interradial area proper, 

 making six plates in the area. The last one, however, is fol- 

 lowed by a long narrow plate, that separates the tertiary radials 

 and unites with the plates of the vault. 



There are eight plates in the azygous area. The first one is 

 in line with the first radials, and of the same size; it is equally 

 as tumid and sculptured in the same manner; it is followed by 



