WEST INDIAN STARFISHES 71 



1 :2. Marginal plates are eight in each row. The two series are 

 not quite opposite. 



The dorsal surface is covered with rather thin and relatively 

 large imbricated plates, overlapping adcentrally, and adradially, 

 forming rows subparallel with the median radial row. Two rows 

 each side of the median radial row have plates larger than the 

 median, flat, thin, imbricated toward the median, with the free 

 edge curvilinear and slightly notched or crenulate, and bearing 

 three to five minute, acute, marginal, appressed spinules. Rest 

 of the surface without spinules and not obscured by dermis. 

 Isolated small papulae are situated adcentrally to these plates, 

 one or two under the free edge of each, except distally. These 

 are followed toward the interradial margin by two short curved 

 rows of similar, but smaller, plates without papulae between them. 



The median radial row of plates is narrow but distinct. Close 

 to the tip of the ray the plates are small and regular, angular, 

 and lie flat, with no pores between. Soon they become notched 

 and turned up with two papular pores under the free edge. 

 Proximally they stand up nearly edgewise and become smaller 

 and are depressed below the level of the adjacent rows of plates. 

 They bear two or three minute acute marginal spinules. The 

 basal radial plates are much larger, but stand up obliquely, 

 showing only one edge and part of the side. Each bears five or 

 six minute spaced spinules on the proximal margin, and three 

 or four scattered on the surface. 



At the base of the interradial areas are two similar closely 

 joined or united plates, of larger si^e, with a notch between them, 

 from which a narrow naked line runs down to the interradial 

 margin. The small madreporite lies in, or partly above, the 

 notch between two of these plates, which with the basal radials, 

 form a raised rim, surrounding a central group of smaller plates, 

 mostly rounded, and having few minute marginal spinules. 



The superomarginal plates, which in the larger specimens 

 number nine or ten, are rather larger and thicker than the 

 radial plates, and a little convex, with curved outer and inner 

 margins. Each one bears two (rarely one) small submarginal 

 spinules on the outer side. 



The infer omarginal plates are similar in size and number, but 

 more prominent, with the edge rounded, forming a rather thin 



