INVERTEBRATES. 239 



Subradial plates somewhat unequal, a little wider than long, 

 four of them apparently hexagonal, and one on the anal side 

 heptagonal. First radial plates about twice as large as the 

 smaller of the subradials, hexagonal in form, and all wider 

 than long, the upper horizontally truncated side being longer 

 than either of the others. Second radials about the size of the 

 first, pentagonal, a little wider than high, truncated below, and 

 provided with a salient angle in the middle above.; all rounded 

 on the outer side, and a little concave on each short lateral 

 margin. 



First anal plate. rather large, or equaling some of the sub- 

 radials in size; irregularly pentagonal or hexagonal in form, 

 and resting between the superior sloping sides of two of the 

 subradials; supporting on its right sloping side an inferior edge 

 of one of the first radial pieces, while it supports two smaller 

 pieces in the second range, the exact form of which cannot be 

 made out in our specimen. 



Arms long, robust, subcylindrical, rather unequal in size, 

 and apparently all simple after the division on the second 

 radials, entirety composed of a single series of pieces, a few of 

 the first of which are longer than wide, and alternately longer 

 and shorter on opposite sides; farther up they become more 

 regular, and shorter than wide. Column rather small, or less 

 than the diameter of the largest arms, round, and composed of 

 thin, slightly unequal segments, near the body. Its central 

 cavity small, and presenting a regular pentapetalous section. 

 Height of body to the summit of the second radials, about 0.50 

 inch; breadth near j;he same. Length of arms apparently not 

 less than 2.50 inches; breadth of do., from 11 to 0.16 inch. 



