456 PSEUDOBOLETIA INDIANA. 



Pseudoboletia indiana 



! Toxopneustes indianua Mien., 1862, Maill. Bourbon, Ann. A. 

 \ Pseudoboletia indiana A. Agass., 1872, Rev. Ech., l't. I. p. 153. 



PL V.f. 8, 9. 



The outline of this species is more conical in profile; test thinner; tuber- 

 culatum relatively smaller, in proportion to the size of the test, compared to 

 P. granulata. The striking difference, however, is in the proportion of the 

 actinostome to the diameter of the test : the actinostome being considerably 

 more than one third the diameter of the test. The actinal cuts are shorter, 

 but broader, and the interambulacral lips of the cuts quite well developed. 

 The actinal membrane was missing in all the specimens examined. The spines 

 of this species are comparatively shorter than those of P. granulata, resem- 

 bling more the spines of the short-spined variety of Toxopneustes variegatus. 

 In a specimen measuring about 54" 1IU in diameter, the actinal surface is 

 quite flat; actinostome not sunken ; there are six vertical rows of primaries 

 at the ambitus ami an irregular median one. The scrobicular circles are large, 

 with numerous small miliaries arranged parallel to the sutures of the plates 

 and vertically between the primaries. Secondaries few in number, irregularly 

 scattered. In the median interambulacral space; the primary tubercles be- 

 come very small and unimportant towards the abaetinal pole, and tubercles 

 of the exterior vertical row also diminish rapidly in size above the ambitus. 

 In the ambulacral space there are four such primary vertical rows of tuber- 

 cles, scarcely smaller than those of the interambulacral space, disappearing 

 towards the abaetinal system in the median ambulacra] as in the median in- 

 terambulacral space. The poriferous /.one is broader than in its congener, and 

 the coronal plates narrower. The abaetinal system does not differ materially ; 

 the anal system is perhaps somewhat smaller. Ocular plates rectangular, 

 two adjacent to anal system. Genital plates very unequal in size; madre- 

 poric genital much larger than the others. Test of a dull yellowish ground- 

 color, with darker patch of brown round abaetinal system, and a broken 

 ring of similar brown patches in the median ambulacral and interambulacral 

 space about half-way from pole to ambitus. A second irregular mottled 

 ring follows the line of the ambitus. The spines are of the same tint as the 

 test, and irrejrularlv mottled or banded with brown. 



Philippine Islau>l> ; Mauritius. 



