120 BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



Geographical range. Hawaiian Islands; Celebes; Fiji; Kermadec Islands; off 

 southeastern Australia; Laccadive Islands; Canary Islands and northward to Cape 

 Carvoeiro, Portugal. 



Bathymetrical range. From 649 (?640) to 2,468 meters. 



Thermal range. From 2.2 to 9.6 C. 



Remarks. The genus Stiremetra should be considered as a tentative grouping of a 

 rather heterogeneous assemblage of forms most of which are known from one or a few 

 mutilated individuals. 



The included species are all small and delicate, and all are from deep water. Most 

 of the individuals are badly broken in the long journey in the dredge from the bottom 

 to the surface intermixed with other stouter and tougher organisms, and few are re- 

 covered in a condition permitting satisfactory description. 



Stiremetra lusitanica is a rather anomalous species, though there seems to be no 

 good reason for not considering it congeneric with at least some of the other species 

 included in Stiremetra. It is the only species having more than 10 arms, the IIBr 

 series being either 2 or 4(3+4); but the majority of the individuals appear to have 10 

 arms only. Its centrodorsal is large with the cirri arranged roughly in 15 columns 

 instead of in 10 definite columns, and it is the only species of the genus known from the 

 Atlantic. 



Another anomalous species is S. breviradia in which the brachials bear long over- 

 lapping spines which at first sight suggest those of Stylometra spinifera. But the resem- 

 blance is undoubtedly superficial, for in its other characters S. breviradia agrees with 

 the species grouped in Stiremetra. 



It is possible that the two species in which the axillaries are shield-shaped and 

 longer than broad, S. acutiradia and S. perplexa, represent a special group, but both are 

 incompletely known, and in general the length of the axillaries is a variable feature much 

 influenced by growth changes. 



Stiremetra spinicirra is remarkable for the great development of the cirrus spines, 

 and S. decora is the only species with highly developed ornamentation; it is also the 

 species recorded from the least depth. Stiremetra carinifera is known from such 

 fragmentary material that little can be said about it; it is, however, the only repre- 

 sentative of the genus known from the Indian Ocean. 



KEY TO THE SPECIES IN THE GENUS STIREMETRA 



a 1 . Cirri with 50-66 segments, six or more of the basal without dorsal spines; IBr series and lower 



brachials with a rounded median ridge; large, the arms up to 80 mm. long. 



fci. Cirri more or less irregularly arranged on the centrodorsal, roughly in 15 columns; 10-14 (usually 

 10) arms about 60 mm. long; cirri nearly 30 mm. long with 50-56 segments (Canary Islands 



to Cape Carvoeiro, Portugal; 1,280 [?914]-2,165 meters) lusitanica (p. 121) 



b 1 . Cirri arranged in 10 columns on the centrodorsal; always 10 arma 



c>. Brachials beyond the proximal fourth of the arms with the dorsal midline raised and pro- 

 duced distally over the base of the brachials succeeding forming, in lateral view, high and 

 conspicuous curved overlapping spines; IBr series and first two brachials smooth dorsally, 

 with straight sides, the carination low and broad or obsolescent; arms about 80 mm. long; 

 cirri with 40-50+ segments (Fiji to the Kermadec Islands; 1,152-2,285 meters). 



breviradia (p. 126) 

 c 2 . Brachials with the dorsal surface not raised into prominent dorsal overlapping spines. 



(P. Axillaries shield-shaped, very long, half again as long as broad, smooth, very sharply 

 flattened laterally, the edges unmodified; IBri with the central portion of the dorsal 



