52 HOLOPUS RANGII. 



gies. When contracted the arms are rolled in a spiral, and pressed laterally 

 against one another so as to enclose a hermetically closed cavity (Figs. 2, 7, S). 

 At the eighth or tenth joint the arm contracts suddenly, and becomes wedge- 

 shaped outside, so as to fit more closely against its neighbors (Fig. 5), the rest 

 of the arm being rolled up inside of the cavity. The cirrhi of the arms are 

 formed of broad, flat joints, fitting also closely to their neighbors, and rolled 

 up spirally towards the ambulacra! channel of the arm when contracted 

 ( Figs. 2, 7, 8). The mouth is surrounded by five triangular plates, by which 

 it can be apparently almost or entirely closed (Figs. 5, 9). These pieces are 

 deeply and irregularly corrugated on the outside. The intervals of the plates 

 or angles of the mouth correspond to the ambulacral channels. There is a 

 small triangular plate in one of the interambulacral spaces inside of the axial 

 joints, which is probably an anal plate, but no opening can be detected near 

 it (Fig. 9). The internal or digestive cavity could not be examined. 



The specimen was obtained at Barbados by a fisherman, who brought it 

 from deep water upon his hook ; it has lost four of its arms, but is otherwise 

 complete. It is dry and of black color, somewhat lighter on the arms. The 

 whole specimen in its contracted state is about one inch and three fourths 

 high. 



