122 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



pentagonal, half again as broad as long, with the distal edges slightly everted. The 

 IIBr series are 2. 



The arms are 10-18 (usually 12-15) in number, from 20 to 75 mm. (usually from 

 50 to 70 mm.) in length. The first brachials are interiorly in close contact, or free. 

 The first 6 or 7 brachials are oblong and those following are wedge-shaped, the longest 

 being as long as broad. The bases of the arms are remarkably smooth, and the 

 distal brachials do not overlap. 



Syzygies occur between brachials 1 + 2 on the inner arms from each IIBr series 

 and 3 + 4 on the outer, then between brachials 12 + 13, 17 + 18, 21 + 22, and distally 

 at intervals of 3 muscular articulations. 



The first 3 pinnules bear combs. In one specimen P 4 occasionally bears a comb 

 of 5 teeth; it consists of 17 segments. P! is from 5 to 7 mm. (usually 5 to 6 mm.) in 

 length with 22-28 segments, of which the first 2 are short and the remainder are 

 half again as long as broad; the distal 7-9 segments bear teeth. P 2 is from 3.2 to 

 5 mm. long with 17-22 segments, of which 5-7 (usually 6) bear teeth. P 3 is from 

 3 to 4 mm. long with 17-21 segments, of which 5-7 bear teeth. P 4 is from 3.5 to 

 4.5 mm. in length with 14-16 segments which are somewhat spinous; it bears no comb. 

 P 6 is 4 mm. long with 15 segments. P 6 is 3.5 mm. long with 14 segments. The distal 

 pinnules are from 5 to 7.5 mm. long with 15-20 (usually 17-18) segments, of which 

 the first is short and those following are half again as long as broad; the distalmost 

 bears small hooks 



The disk is from 3.5 to 4 mm. in diameter, colored dark brown with calcareous 

 concretions. The mouth is central. The anal tube is short, 1.2 mm. long. 



Notes. In one specimen from station 53 with 15 arms 20 mm. long and the disk 

 2.5 mm. in diameter P 2 is sometimes and P 3 is always absent. 



Localities. Dr. Sixten Bock's station 53 ; Bonin Islands, 2 miles east of Higashi- 

 jima; 164 meters; sand and broken shells; August 7, 1914 [Gisle"n, 1922]. 



Dr. Sixten Bock's station 55; Bonin Islands, eastnortheast of Chichijima; 

 210 meters; August 15, 1914 [Gisle"n, 1922]. 



Dr. Sixten Bock's station 56; Bonin Islands, east of the channel; 210 meters; 

 August 15, 1914 [Gisle"n, 1922] (1, U.S.N.M., E. 1109). 



Dr. Sixten Bock's station 59; Bonin Islands, eastnortheast of Anojima; 183 

 meters; August 15, 1914 [Gisle"n, 1922]. 



Geographical range. This species is only known from the Bonin Islands. 



Bathymetrical range. From the records apparently 164-210 meters; but the 

 depths as given represent the length of line out, not the actual depths. 



Remarks. This species is known only from the specimens collected by Dr. 

 Sixten Bock in 1914 and described in detail by Dr. Torsten Gisle"n in 1922. 



Genus NEOCOMATELLA A. H. Clark 



Anledon (part) POURTALES, Bull. Mus. Comp. Zool., vol. 5, No. 9, 1878, p. 216, and following 



authors. 

 Actinometra (part) P. H. CARPENTER, Bull. Mus. Comp. Zool., vol. 9, No. 4, 1881, p. 158, and 



following authors. 



Actynometra (part) FILHOL, La vie an fond des mers, 1885, p. 213. 

 Comasler (part) A. H. CLARK, Proc. U. S. Nat. Mus., vol. 33, 1908, p. 686. 



