INVERTEBRATES. 291 



middle of its lower margin. Anal plate as long, and three- 

 fourths as wide, as the first radials, contracted a little above. 

 Second radials very small, rudimentary, or possibly some- 

 times obsolete, not generally very readily distinguished from 

 the minute secondary radial and first brachial pieces ; sup- 

 porting above, the brachial pieces of the two inner arms, and 

 on their short outer sloping sides, the short inner sides of the 

 two minute secondary radial pieces, which, however, also rest 

 mainly down upon the first radial pieces, and support the two 

 outer arms of each ray. 



First two or three arm pieces much larger than the others, 

 closely connected laterally, and consisting of a single range to 

 each arm. Above these they soon pass into double ranges of 

 small, alternating pieces, which are three or four times as wide 

 as long, and bear on their inner sides a double series of ten- 

 tacles. Arms (of which there are four to each ray, or twenty 

 in the entire series) round on the outer side, and deeply grooved 

 within, slightly tapering, apparently rather long and entirely 

 simple. Tentacles slender, very closely arranged, and com- 

 posed of joints which are three or four times as long as wide. 

 Interbrachial appendages arising from the middle of each group 

 of arms, thin or knife-like on their outer edges above, much 

 thicker below, and apparently nearly or quite as long as the 

 arms. Height of body to summit of first radials, 0.33 inch; 

 breadth of do. just below the arms, 0.84 inch; breadth of 

 base, 0.60 inch; height of do., 0.16 inch. Breadth of arms, 

 0.12 inch. 



