CYSTECHINUS LOVENI. 



161 



terior genitals and the posterior oculars, also varied greatly in outline and 

 size, Fig. 230 (PI. 79, figs. 1-3). In Cystechinus the ocular plates are not 



Outside view. 88 mm. 



Fig. 229. C. Loveni. 



Inside view 85 mm. ? 



Fig. 230. Cystechinus Loveni. 



infrequently imperforate in older specimens (PI. 78, fig. G), Fig. 231. In a 

 smaller specimen of 20 mm. the abactinal system (PI. 79, fig. 4) resembles 

 somewhat that of Urechinus, Fig. 232. 



4 



88 mm. 



Fig. 231. C. Loveni. 



Outside. 20 mm. ? 



Fig. 232. C. Loveni. 



The actinal system is elliptical, the actinostome is subcentral placed 

 towards the posterior edge (PL 79, figs. 3, 5). The anterior part of the 

 actinal membrane is covered with an outer row of large triangular plates 



n 



