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PROCEEDINGS OF THE NATIONAL MUSEUM. 



VOL. 37. 



proximal to them, a cluster of the peculiar umbrella-shaped spines, 

 characteristic of the genus. Tentacle scales, two at each basal pore, 

 one proximal and one distal, broadly spatulate; beyond the fifth 

 or sixth pore only the proximal scale is present, and it becomes 

 longer and more pointed. Color (dried from alcohol) dull yellowish. 

 Locality. — Albatross station 2750, east of the Danish West Indies; 

 lat. 18°30'00"N.; long. 63° 31' 00" W.; 496 

 fathoms; temperature, 44.5° F.; fine gray 

 sand: 2 specimens. 



IVpe.— Cat. No. 25829, U.S.N.M., from 

 station 2750. 



It is a matter of some interest that this 

 genus, hitherto known only from the Pacific 

 Ocean, should be found in the Caribbean 

 Sea. The Caribbean species resembles mul- 

 tispina Koehler, in the larger number of arm 

 spines and in the form and arrangement of 

 the tentacle scales, more than it does suj)- 

 plicans Lyman. But it is easily distin- 

 guished from either of those species by the shape of the arm plates. 

 Only a single unbroken umbrella spine was found, but the minute 

 points of attachment, from which they had been knocked off, are 

 evident on the side arm plates. It is obvious that in the living 

 animal these little "umbrellas" are very numerous, and it would be 

 most interesting to know whether they have any particular function, 

 and if so, what it is. 



Fig. 2.— Upper surface of the 

 ninth, tenth and eleventh 

 arm-joints of opuiotholia 

 mitrephora, showing the 

 small upper arm-plates and 

 the arm-spines. x 10. 



