ECHINODERMATA—CYSTOIDEA. 



471 



23. S. bloomfieldensis Schuchert. Siluric. 



Calyx depressed globular; length 14 mm.; diameter 15 to 16 

 mm. Base not excavated. 



Manlius of Pennsylvania. 



XIV. Malocystites Billings. 

 Calyx globular, composed of 40 or 50 thick and solid plates. 

 Arms recumbent, in two groups, varying in number, connected 

 by a short groove. Pores and 

 pore-rhombs absent. Ordo- 

 vicic. 



Fig. 1782. Malocystites murchisoni, 

 right and left side. tz, ambulacra ; w, 

 mouth. (After Billings.) 



24. M. murchisoni Billings. 



(Fig. 1782.) Ordovicic. 



Plates covered with small 

 tubercles. Arms in two 

 groups of four each, con- 

 nected by a short groove. 

 Usual diameter about one inch. 



Chazy of Quebec. 



25. M. barrandii Billings. Ordovicic. 

 Plates smooth or very minutely granulated. Arms two and 



very short, connected by the ambulacral groove. 

 Chazy of Quebec. 



(Type of genus.) 



Fig. 1783. Malocystites emmonsiy oral and side view of type, X 4' 

 (After Hudson.) 



26. M. emmonsi Hudson. (Fig. 1783.) Ordovicic. 



Smaller than the preceding species and with the globular calyx 

 irregularly angular. Arms two, connected in the form of a sigma. 



Chazy of New York. 



