380 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



in O. fluctuant, and they become as long as broad toward the fii- 

 teenth. The form of the mouth shields is also very different; they 

 are larger, usually longer than broad, with a strong notch on the 

 sides corresponding to the bottom of the genital slits in 0. flagellata, 

 and simply triangular, as long as broad, or even a little broader 

 than long, with the outlines very much more simple in 0. fluctuans. 

 The arm spines are relatively stouter and thicker in 0. flagellata, 

 and the dorsal spine especially is more developed than in 0. fluc- 

 tuant. The ventral interradial areas are narrower than in O . flagel- 

 lata, resulting from the broadening of the arms, but the plates here 

 are more numerous and smaller than in the new species in speci- 

 mens of the same size. 



It has therefore not seemed to me possible to unite the two forms 

 in the same species, and the differences which I have given, espe- 

 cially regarding the width of the arms and the form of the mouth 

 shields, can not be attributed to a difference in the age of the indi- 

 viduals. 



OPHIURA IRRORATA (Lyman). 



See for the bibliography : 

 Ophiura irrorata H. L. Clakk ('13), p. 209. — Matsumoto ('15), p. 81. — 



H. L. Clark ('15), p. 320.— Matsumoto ('17), p. 277. 

 Ophioglypha irrorata Kcehler ('14), p. 18. 



Localities. — Albatross station 5602; Gulf of Tomini, Celebes; Go- 

 rontalo Pier bearing N. 13.16 kilometers (7.1 miles) distant (lat. 

 0° 22' 00" N., long. 132° 03' 30" E.) ; 1,759 meters (962 fathoms) ; 

 November 14, 1909 ; gy. M. 



One specimen (Cat. No. 41343, U.S.N.M.). 



Albatross station 5614; Molucca Passage; Tifori Island (C.) bear- 

 ing N. 19° E., 56.52 kilometers (30.5 miles) distant (lat. 0° 31' 00" 

 N., long. 125° 58' 45" E.) ; 2,012 meters (1,100 fathoms) ; Novem- 

 ber 22, 1909 ; gy. M., S., Glob. 



One specimen (Cat. No. 41342, U.S.N.M.). 



Notes. — The diameter of the disk is 15 mm. in the specimen from 

 station 5602 and 19 mm. in the other ; in both the arms are broken 

 off near the base. 



In the specimen from station 5602 the arrangement of the plates 

 on the dorsal surface of the disk recalls one of the figures published 

 by Liitken and Mortensen ('99), pi. 1, fig. 10) under the name of 

 O. twmulosa, with small, distinct primary plates. The mouth shields 

 are a little broader than long; the upper arm spine is rather elon- 

 gated, and its length exceeds a third of the segment. In the other 

 specimen the primaiy plates are no longer distinct and the dorsal 

 spine is very much smaller. Regarding the synonymy of this spe- 

 cies, as well as its geographical distribution, which is very exten- 

 sive. I refer to my memoir of 1914, to which I have nothing to add. 



