250 BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



The club spines which cover the dorsal surface of the disk of 0. 

 caespitosa are finer and more elongated, and they are furnished with 

 finer spinules than in 0. marenzelleri. In the single specimen which 

 I have a few spines are mingled with the club spines, a feature which 

 Lyman did not mention but which H. L. Clark found in some 0. 

 caespitosa from Australia collected both by the Thetis (H. L. Clark, 

 '09, p. 549) and by the Endeavour ('16, p. 90). The upper and under 

 arm plates have almost the same form in the two species, but the arm 

 spines are more slender and more finely denticulate, and not broad- 

 ened at the extremity in 0. caespitosa, and they are nine instead of 

 only seven in number ; but the mouth shields especially are very much 

 broader than long, while in O. marenzelleri they are scarcely broader 

 than long and their form is almost lozenge-shaped. 



The specimens from the Vienna Museum upon which I based 0. 

 marenzelleri came from Japan. 



Matsumoto ('17, p. 220) has recorded 0. marenzelleri from various 

 localities in Japan, at depths between and 70 fathoms. He dis- 

 tinguished a littoral form, in which the disk is uniformly covered 

 with echinulated and closely crowded spines, and a sublittoral form 

 in which the disk bears club spines ending in numerous spinules. He 

 also considers 0. marenzelleri as closely related to O koreana which 

 the sublittoral form especially approaches, and he gives 0. hylodes 

 H. L. Clark as a synonym of marenzelleri. 



OPHIOTHRIX MARTENSI Lyman. 



See for bibliography : 



Ophiothrix martensi KOSHLEB ('05), p. 80; ('07), p. 334; ('07b), p. 252; 

 ('10), p. 294. MACINTOSH ('11), p. 162. H. L. CLARK ('15), p. 275. 



Localities. Albatross station 5141; vicinity of Jolo; Jolo Light 

 bearing S. 17 E., 10.19 kilometers (5.5 miles) distant (lat. 6 09' 00" 

 N., long. 120 58' 00" E.) ; 53 meters (29 fathoms) ; February 15, 

 1908; co. S. 



One specimen (Cat. No. 41264, U.S.N.M.). 



Albatross station 5145; vicinity of Jolo; Jolo Light bearing S. 16 

 E., 1.57 kilometers (0.85 mile) distant (lat. 6 04' 30" N., long. 120 

 59' 30" E.) ; 42 meters (23 fathoms) ; February 15, 1908; co. S., Sh. 



Three specimens (Cat. No. 41263, U.S.N.M.). 



Albatross station 5147; Sulu (Jolo) Archipelago, in the vicinity 

 of Siasi; Sulade Island (E.) bearing N. 3 E., 15.57 kilometers (8.4 

 miles) distant (lat. 5 41' 40" N., long. 120 47' 10" E.) ; 38 meters 

 (21 fathoms) ; February 16, 1908; co. S., Sh. 



Six specimens (Cat. Nos. E. 17, E. 18, U.S.N.M.). 



Albatross station 5554; Jolo Island and vicinity; Cabalian Point 

 (Jolo) bearing N. 76 E., 7.04 kilometers (3.8 miles) distant (lat. 5 



