JAPANESE ASÏEEOIDEA. 289 



broad, and except for the very occasional plates intercalated be- 

 tween the inferomarginals, there are as many of them as there 

 are inferomarginals, each adambulacral being in a line with the 

 inferomarginal plate just outside it. There is however a hardly 

 noticeable break in the armature between the two series of plates, 

 as is also indicated by Müllek and Teoschel in their description. 

 This break may be caused by a distinct furrow, or the furrow 

 may be entirely absent. The difference of armature between the 

 inferomarginal and adambulacral plates is also easily noticeable 

 on an actinal view, inasmuch as the spiniferous part of the adam- 

 bulacrals is more restricted than on the inferomarginals, and the 

 farrowed spaces between two contiguous adambulacral plates are 

 consequently larger and more conspicuous. The armature of the 

 adambulacral plate consists of a transverse series of three large 

 spines on the inner half of the plate, a number (10-15) of small 

 spines on the outer half, and one or more, elongated, pyramidal 

 pedicellarige with three cusps, situated at the outer end of the series 

 of large spines (PI. V, fig. 83). The first adambulacral spine is 

 smaller than the other two and are somewhat flattened and curved ; 

 the second spine is the largest of the three and is also slightly 

 curved and flattened ; the third spine is only shghtly smaller than 

 the second and is nearly straight and round. Occasionally the first 

 spine is duplicated and in such a case there are four large spines 

 on one adambulacral plate. Close to the third adambulacral spine, 

 and usually on its proximo- external side there is on most of 

 the adambulacral plates one, or occasionally two, tricuspid large 

 pedicellariae of the form of a triangular pyramid, only shghtly shorter 

 than the spine itself (PI. V, fig. 84). The rest of the actinal surface 

 of the adambulacral plate is covered with small spines, which may 



