I >I ALITHOCIDARIS GEMMIFERA. 



57 



obliquely at the outer edge of the plates. Fig. 86 (PI. 23, fig. 3), except on 

 the actinal plates, where the lower pair of pores is pushed toward the 

 median line, Fig. 87 (PI. 23, figs. /, J,). There are three pairs of pores to 

 each ambulacra! plate. 



Fig. 86. 



DlAMTHOCIDAK.6 GEMMIFERA. 



The actinal system is marked by the existence of five large elongate 

 areas composed of minute calcareous plates placed between the actinal 

 extremity of the ambulacra and the ring often perforate ambulacral buccal 

 plates ; these plates are thickly covered with miliaries and long-stemmed 

 pedicellarise similar to those of the abactinal system. 



The gills are large (PI. 23, fig. 1), forming a prominent loop or separate 

 clusters. 



The largest primary radioles observed are 8 mm. in length ; they are 

 flattened, fluted (PI. 15. fig. 3), and serrate on the edges (PI. 23, fig. 13). 



The primary tubercles are imperforate. The scrobicular circle is slightly 

 raised from the surface of the test. 



21 mm. 



Int. •_', actinal side. 



Fi<;. 88. 



DlALITHOCIDARIS GEMMIFERA. 



Int. 2, inside. 

 Fig. 89. 



When alive the general coloring of this species is yellowish brown. 



The apical system is thickly covered with short-headed long-stemmed 

 pedicellariae seated upon the minute miliaries scattered in the space be- 

 tween the sutures and that covered with verrucas. Over the whole test are 



