JAPANESE ASTEEOIDEA. 455 



plates. These adcentral, or apical tubercles enclose a central 

 depression, at the centre of which there are three conical tuber- 

 cles, exactly similar in form to the apical ones but about one- 

 third as large, and spreading out at the base into four or five 

 trabecular processes, by which they are joined with one another 

 and with the apical tubercles. The plate next the apical tubercle 

 of each series is also raised into a conical tubercle similar in form 

 to the former but somewhat smaller ; and in some of the radii 

 there is a small, spine-tipped tubercle between the apical and the 

 next tubercle. Besides the two tubercles just mentioned, which 

 are present in all the radii, there are some more (3-7) tubercles 

 in the carinal series, which are much lower than either of the 

 former, but are tipped each with a teat-like spine. The plates of 

 the carinal series, which are not raised into tubercles, are either 

 cruciform or lozenge -shaped, except those near the tip of the arms, 

 which are generally rounded. On either side of the carinal series 

 there are two more longitudinal series of plates in each arm, which 

 are continued into the disk and are there connected with the 

 corresponding series of the adjacent arm by curved series of plates 

 running more or less parallel to the margin of the disk. There 

 are some more plates without any definite arrangement between 

 the outer of the disk series just mentioned and the superomar- 

 ginals of the interbrachium. Some of the plates of the dorso- 

 lateral series of the disk are raised into tubercles which are either 

 conical or mammiform and are tipped with a conical or teat-like 

 spine. 



Both the abactinal plates and the spaces between them are 

 closely covered over with fine granules, among which there are 

 numerous podicellarise, which are of three forms. The most con- 



