CYSTECHINUS LOVENI. 



161 



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

 size, Fig. 230 (PI. 70, 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 (PL 78, fig. 6), Fig. 231. In a 

 smaller specimen of 20 mm. the abactinal system (PI. 70, fig. 4) resembles 

 somewhat that of Urechinus, Fig. 232. 



4 

 88 mm. 



Fig. 231. C. Loveni. 



Outside. 20 mm. ? 



Fig. 232. C Lovexi. 



The actinal system is elliptical, the actinostome is subcentral placed 



towards the posterior edge (PI. 70, figs. 3: 5). The anterior part of the 



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



11 



