16 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



rhombic, not quite twice as broad as long; the lateral angles are just in contact with 

 those of their neighbors, and the distal and proximal angles are similar, the latter 

 being somewhat more rounded. The proximal half of the median line carries a rather 

 high sharp keel with a straight crest. Of the nine IIBr series present, eight are 4, the 

 axillary in no case being united to the preceding ossicle by syzygy, and one is 2. The 

 division series are narrow and high, gablelike in end view, and the middorsal line is 

 occupied by a sharp and conspicuous, though not high, carination. The lateral borders 

 of the ossicles may be sparsely denticulate, but the proximal and distal edges are unmod- 

 ified. The division series are in very close apposition, and the sides of the component 

 elements are sharply flattened. 



Only the arm bases are preserved. There were at least 19 arms. The brachials 

 are deep and much compressed laterally, with a low but sharp median carination, which 

 is obscure on the earlier brachials, though becoming conspicuous as the brachials 

 become triangular. 



Although the occurrence of IIBr series of four elements instead of two would seem 

 at first sight to be an important character sharply distinguishing this form from S. 

 quinquecostata, it is undoubtedly only an aberrant specimen of the latter. The two 

 were taken together, and they seem to agree in every other feature, though the present 

 specimen is slightly smaller than those identified as S. quinquecostata and has somewhat 

 more slender cirri. This would be likely to be the case, however, with any markedly 

 aberrant individual. It is noteworthy that in the IIBr series the two distal elements 

 are never united by syzygy, which would indicate that they are not the morphological 

 equivalent of IIBr series of 4(3+4). These latter are not known to occur in Stenometra, 

 or in any of the closely related genera. The occurrence of IIBr series of four ossicles 

 of which the two outermost are not united by syzygy is not infrequent in comatulids 

 in which the division series are normally 2. I once described under the name of Cyl- 

 lometra anomala (see Part 4b, p. 145) a specimen of C. manca in which six of the seven 

 IIBr series present are of four elements. 



In 1911 I described a new species, Stenometra cristata, from Albatross station 5275, 

 saying that it is nearest S. diadema from southern Japan, but is a smaller and more 

 slender form; the centrodorsal is proportionately smaller, more conical and less columnar, 

 with a finely papillose rounded conical tip; the cirri are about 40 mm. long; the longest 

 cirrus segment, the fifth or sixth, is twice as long as broad or even somewhat longer 

 instead of being but little longer than broad as in S. diadema; the carination of the 

 division series and lower brachials is not quite so high as in S. diadema, and is more 

 regular with a more even profile; the profile is irregular and serrate in S. diadema; 

 the type specimen has 20 arms 85 mm. long. Four smaller specimens with 18, 17, 

 14, and 13 arms, the last two being immature, were secured at the same station. I 

 cannot see that this supposed new species differs in any essential feature from S. 

 quinquecostata. 



Localities. Albatross station 5275; China Sea, in the vicinity of southern Luzon; 

 Malavatuan Island (N.) bearing S. 71 E., 10.75 miles distant (lat. 1355'55" N., 

 long. 12010'15" E.); 214 meters; fine sand; July 16, 1908 [A. H. Clark, 1911, 1912, 

 1918] (6, U.S.N.M., 27501 [type specimen], 35598). 



