204 



the plates are thinner and sharper, and the intermediate 

 spaces more strongly granulose. The column and arms are 

 unknown. 



GENUS GLYPTASTER (Hall). 

 Glyptaster occidentalis (Hall). 

 Body of medium size, broadly subturbinate ; basal plates 

 small, distinctly developed ; subradial plates compara- 

 tively large, marked by a single rounded ridge which 

 bifurcates in the middle of the plate, the divisions going 

 to the sutures of the radial plates. First radial plate 

 large, the lower half marked by two rounded ridges 

 which are continued from the two adjacent subradials, 

 and unite on the middle of this plate, and continuing 

 along the second and third radials, bifurcates on the lat- 

 ter, following the subdivision of the ray. Interradials 

 about three, with one interradial space (the anal) larger, 

 and containing a greater number of plates. 

 Surface of the ridge on the subradial and radial plates 

 marked by longitudinal striae, while all the plates are 

 marked by sharp radiating lines, which are continuous or 

 interrupted, and granulose, the granules are often arranged 

 in more or less confluent lines ; intermediate surface of 

 plates granulose. Column round above. Arms unknown. 



Glyptaster occidentalis. 

 Var. a. 



A specimen of somewhat more robust character than 

 those described, has the ridges of the rays marked with un- 

 dulating, subgranuiose striae, and the plates more distinctly 

 striate, while the anal area is large and subventricose, show- 

 ing three ranges of plates in the order of one, three and 

 four, with a more numerous fourth range. The anterior 

 ray gives some evidence of a second bifurcation before be- 

 coming free from the body. 



