98 



BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



VOLUME 1 



separated. The IBr 2 are rhombic with all the sides concave, and about as long as 

 broad. 



The 10 arms are about 30 mm. long. 



P! is 6 mm. long, composed of 12 or 13 segments of which the first is about as long 

 as broad, the second is about twice as long as broad, the third is about three tunes as 

 long as broad, and the remainder are somewhat longer. P 2 is 4.5 mm. long, similar 

 to PI and with the same number of slightly shorter segments. P 3 and the following 

 pinnules are shorter and slightly stouter with the distal edges of their segments everted 

 and serrate, and with gonads. Distally the pinnules become very slender and increase 

 somewhat in length. 



The color in alcohol is yellowish brown with the pinnules, cirri, and interambulacral 

 areas of the disk white. 



Locality. Albatross station 3938; Hawaiian Islands; Laysan Island Light bearing 

 S. 8830' E., 7.8 miles distant; 270-298 meters; temperature 15.72 C.; white sand 

 and broken shells; May 16, 1902 [A. H. Clark, 1908, 1912, 1917, 1918] (1, U.S.N.M., 

 22692). 



FIGURE 7.- Argyrometra criipa (A. H. Clark), holo- 

 type, laterodorsal view. 



ARGYROMETRA MORTENSENI A. H. Clark 



Argyrometra mortenseni A. H. CLARK, Journ. Washington Acad. Sci., vol. 7, 1917, No. 5, p. 128 (listed), 

 p. 129 (diagnosis; comparison with A. crispa; locality) ; Proc. Biol. Soc. Washington, vol. 31, 1917, 

 p. 41 (listed). GISLEN, Nova Acta Reg. Soc. Sci. Upsaliensis, ser. 4, vol. 5, No. 6, 1922, p. 130. 

 MORTENSEN, Vid. Medd. Nat. Foren. K0benhavn, vol. 79, 1925, p. 386, p. 389 (localities; notes), 

 fig. 66 (calyx and arm bases), p. 397 (listed). FELL, New Zealand Science Congress, 1947, p. 210 

 (listed) ; Tuatara, Wellington, New Zealand, vol. 3, No. 2, 1950, p. 79, text fig. 3 (calyx and arm 

 bases), p. 84 (in key). 



Diagnostic features.' P t is shorter than P 2 , which is shorter than P 3 ; there are 12 

 to 17 cirrus segments. The arms are about 30 mm. long in the holotype. 



Description. The cirri have up to 17 segments, of which the longest are from four 

 to six tunes as long as their distal diameter. The distal ends of the segments are much 

 more expanded than in A. crispa in which then- dorsal and ventral profiles are every- 

 where practically parallel. 



The 10 arms are about 30 mm. long. 



PI is 3.3 mm. long, slender and evenly tapering, composed of 12 segments, of which 

 the first is slightly broader than long, the second and third are very slightly longer than 

 broad, and the following become progressively elongated, being between four and five 



