344 APPENDIX. 



of the upper and lower series alternating ; the edge of the 

 upper ones with some indistinct spines on the margin, the 

 lower ones with scattered mobile spines on the oral surfaces. 



The ossicules of the oral surface, three, four, or six-sided, 

 granular, with one (rarely two) central compressed acute 

 mobile spines. 



The ambulacral spines very small, close, fourteen or six- 

 teen on each ossicule, forming a rounder group, with two or 

 three series of large scattered mobile acute spines on the 

 outer side. 



This genus resembles Stellaster, but differs from it in the 

 oral surface being furnished with scattered spines. 



There is a fossil species very like the one here described 

 found in the chalk, and figured in Mr. Dixon's work on the 

 Fossils of Worthing, which I propose to call Calli derma 

 Dixonii ; there are probably several other fossil species 

 from the same locality, they have been referred to the genus 

 Tosia, but the ossicules are granular, and the oral surface 

 spinose. 



Calliderma Emma, n. s. 



Flat, pentangular, the sides concave, the arms elongated, 

 produced, tapering to a fine point, about two-thirds the 

 length of the diameter of the disks. 



The dorsal ossicules six-sided, regular, flat-topped, co- 

 vered with minute roundish granules, the central granules 

 of the central ossicules and those down the centre of the 

 arms larger, globular, tubercular- like 



The margin sharp-edged, concave in the centre ; the ossi- 

 cules of the upper and lower series alternating, minutely 

 granular, with one or two larger subspinose granules on the 

 middle of the upper margin. Marginal ossicules about 50 

 on each surface on each side ; the lower series with scattered 

 acute compressed spines on their oral sides. 



