ANOCHANUS. 559 



petals the outer poriferous zones extend to the actinostome as independent 

 disconnected pores till they reach the phyllodes, when the pores become 

 again large, and arranged in two irregular rows diverging from the actino- 

 stome. The ambulacral petals are narrow, elongate, flush with the test; the 

 poriferous zones are as broad as the median interporiferous space ; the pores 

 are round, large, distinct ; outer row the largest, connected by a shallow fur- 

 row. The median odd posterior interambulacral line forms an indistinct 

 rounded keel from the vertex to the apical system. The tuberculation is 

 uniform over the whole abactinal surface, closely crowded with large miliaries, 

 mounted on the ridges separating the pits in which the tubercles are placed. 

 In the anal groove the tuberculation is reduced to a mere granulation ; on the 

 actinal surface the tubercles are more distant, the miliaries between them 

 less crowded. The steep sloping sides of the actinostome are covered with 

 closely packed uniform miliaries, barely forming traces of bourrelets on the 

 upper edges. None of the specimens of this interesting species, either in 

 the Berlin. London, or Stockholm Museums, had retained their spines ; they 

 were merely bleached tests, like the one figured in PI. XIX b . 



East India Islands. 



(ECHINOBRISSUS.) Axochanus. 



Anochanus Grube, 1868, Monatsb. Akad. Berlin, March, p. 178. 



This subgenus is retained for a remarkable sea-urchin, with which future 

 investigations must make us more familiar before we can decide its generic 

 affinities. The test resembles in outline Echinobrissus ; has the same anal 

 groove ; the ambulacra, according to Grube, run uninterruptedly from the 

 apex to the actinostome. The apical system is wanting, and is replaced by an 

 opening leading into a genital cavity which does not communicate with the 

 interior of the test, and in which the young are found. This abnormal mode 

 of development in sea-urchins seems to correspond to the viviparous mode of 

 development of some Ophiurans and Starfishes, in which the Pluteus is 

 never pelagic ; but we must await the publication of Grube's memoir 

 for further information regarding the single species of this genus thus far 

 found . 



