JAPANESE ASTEROIDEA. 



171 



flattened spines is always present on each inferomarginal, the 

 spines becoming longer toward the margin, the last, usually the 

 largest, being found very close to the abactinal margin of the 

 plate. There may sometimes be detected a second row 

 of smaller spines, but more commonly these are not developed 

 well enough to show distinctly. The outer half of the fasciolar 

 grooves between the inferomarginals is covered with capillary 

 spinelets similar to those of the super omarginals, and continuous 

 w^ith them. 



Adambulacrals. — The adambulacrals are about one-third as 

 broad as the inferomarginals, and there are usually two of them 

 to each inferomarginal, but in a few places in each arm there 

 may be five of them to two inferomarginals. The spines may be 

 represented by the following formulae. 



Specim. 1 1:2:2, which means that there is an apical spine, 

 followed by a pair, and then a second pair. This 

 was found in some small specimens with r=5-8 mm., 

 and represents probably the simplest case of ad- 

 ambulacral armature in this species. The following 

 variations have been observed. 

 1:2:2:3 or 1:2:2:2:1 

 2:2:4 



Specim. 2 



2 

 3 

 4 

 5 

 

 / 



1 

 1 

 1 

 1 

 1 



2:2:5 



9.0.9 



-J • -J • -J 



2:3:2 



9.9-9 



3 

 3 

 9 



the total number of spines amounting up to ten or eleven (PI. Ill, 

 fig. 46). The first or apical spine is always much longer than 

 the rest ; of the first pair the two may or may not be of the 



