334 s. CKxro : 



marginals and are like the medium sized ones found on the paxillaî. 

 AdamhulacraU. — The adambulacral plates are nearly square 

 and the armature consists of three rows. On the furrow edge is 

 a series of six or seven, subequal, ilattened, long spines, which, 

 when those of both sides are bent towards tlie furrow, form 

 veritable cheuaiLV-de-frise for the latter (PI. XIII, fig. 195,197). 

 Separated from this furrow series by a groove, is the second 

 series of armature consisting of three or four, or sometimes five, 

 short spines of a four-sided prismatic form, with rather sharp ends. 

 The spines at the two ends of the scries are shorter and the one 

 at the adcontral end is usually shorter than the one at the other end. 

 The third row consists mostly of four, sometimes three or five, 

 granules similar to those of the ventrolateral plates. On some of 

 the plates the granules at the abcentral end of this series is 

 dupHcated, and towards the tip of the arms the entire row is 

 usually doubled. 



Mouth-plates. — The mouth-plates are relatively small and in- 

 conspicuous. The distal end is naked, and there is a quite con- 

 spicuous central space for the two paired plates (PI. XIII, fig. 

 196). On the furrow margin of each plate is a series of ten 

 flattened, subequal spines closely set side by side. The mouth 

 being rather tightly closed in my specimen, these spines all stand 

 up erect. On the inner side of this series is a second row of 

 some six, shorter and stouter spines, parallel to the former. 

 Then follows a third series of some four spines, smaller in all 

 respects than those of the second row. Some of the spines of 

 the last two rows may assume such a position that they form a 

 direct continuation of the first series. The third series may also bo 

 totally wanting, e.g. on one side of fig. 196. 



