A MONOGRAPH OF THE EXISTING CRINOIDS 347 



(P. Smaller, arms 70-110 mm. long; 25-35 cirrus segments of which the outer bear long and 



sharp dorsal spines. 



e*. Synarthrial tubercles obsolete; pinnules slender with 17-18 segments, of which the basal 

 are distinctly, though narrowly, carinate, and the outer have everted and dentate 

 distal ends; arms up to 110 mm. long (southeastern New Guinea to Tonga and Fiji; 



littoral).. _. tessellata papuensis (p. 385) 



e*. Synarthrial tubercles prominent, though broad and blunt; lower pinnules stout with 

 about 15 segments of which the basal are not carinate and the outer are entirely 



smooth; arms 70-95 mm. long (Japan) laevipinna (p. 389) 



c 2 . Synarthrial tubercles extravagantly developed and produced; 23-40 (usually 30-35) cirrus 

 segments; arms 80-120 (usually 80-100) mm. long; cirri 23-30 mm. long (Singapore; 0-13 

 meters).. ensifer (p. 387) 



AMPHIMETBA SPECTABILIS A. H. Clark 



PLATE 38, FIGURE 177; PLATE 39, FIGURES 183, 184 

 [See also vol. 1, pt. 2, fig. 193 (lateral view), p. 117.] 



Himerometra milberli (part) A. H. CLARK, Smithsonian Misc. Coll., vol. 52, 1908, p. 215 (Albatross 

 station 5100), p. 216 (cirri compared with those of Himerometra discoidea). 



Amphimetra milberti (part) A. H. CLARK, Proc. Biol. Soc. Washington, vol. 22, 1909, p. 7 (listed); 

 Vid. Medd. Naturh. Foren. K0benhavn, 1909, p. 156 (the species referred to under this name 

 in the discussion of A. molleri); Die Fauna Siidwest-Australiens, vol. 3, Lief. 13, 1911, p. 459 

 (comparison with a specimen of discoidea [in reality tessellata]); Mem. Australian Mus., vol. 4, 

 1911, p. 767 (record from Philippine Islands); Proc. U. S. Nat. Mus., vol. 39, 1911, p. 540 

 (Limborres Cave); Crinoids of the Indian Ocean, 1912, p. Ill; Rec. Western Australian Mus., 

 vol. 1, pt. 3, 1914, p. 124 (comparison with discoidea [= tessellata]). 



Amphimetra spectabilis A. H. CLARK, Unstalked crinoids of the Siboga-'E^ped., 1918, p. 82 (in key; 

 range), p. 83 (references; localities from which known). 



Diagnostic features. A large stout species with the arms 200 mm. long; the cirri 

 are large and very stout, curved throughout, with 45-51 segments, most of which are 

 about four times as broad as long; dorsal spines are developed from the sixteenth or 

 seventeenth segments onward. 



Description. The centrodorsal is thick discoidal with a very strongly convex 

 dorsal pole, which is almost completely covered with obsolete cirrus sockets rapidly 

 decreasing in size toward the center. The cirri are arranged in two alternating mar- 

 ginal rows. The centrodorsal measures 6 mm. in breadth at the base and 4 mm. in 

 height, and the bare dorsal pole is 4.5 mm. in diameter. 



The cirri are XVIII, 45-51, 45 mm. in length, very stout, tapering slightly in the 

 distal half, flexible throughout and usually curved for their entire length. The dorsal 

 surface is somewhat flattened. The segments are subequal, most of them being 

 about four times as broad as long. The last five or six decrease in width and become 

 relatively longer, so that the antepenultimate is about twice as broad as the median 

 length and the penultimate is but little broader than long. The distal ends of the 

 segments are slightly thickened, especially dorsally and ventrally, and also roughened, 

 projecting beyond, but not overlapping, the bases of the segments succeeding. The 

 fourteenth-seventeenth (usually sixteenth or seventeenth) and following segments 

 bear dorsal spines directed obliquely forward, which, although they arise from nearly 

 the whole dorsal surface of the segments, become at the tip slender, sharp, and glassy. 

 On the last two or three segments before the penultimate these spines become reduced 

 to low pointed median tubercles. The opposing spine is larger than the dorsal 



