10S BULLETIN 82, UNITED STATES NATIONAL MUSEUM 



Geographical range. From the northern Philippines to the Moluccas and the 

 Kermadec Islands, north of New Zealand. 



Bathy metrical range. — From 457 to 1,165 (? 1,264) meters. 



Thermal range.— From 4.17° to 10.2° C. 



Remarks. — There appear to be four readily recognizable species in this genus. Of 

 the six spi'cics heretofore recognized, valida, eupedata, incerta, propinqua, vera, and sul- 

 cata, two are considered synonyms herein, eupedata a synonym of valida and vera a 

 synonym of propinqua. 



The genus Aglaometra appears not to differ appreciably from Stiremetra except in 

 the greater size of the included species, which have the IBr series and lower brachials 

 more broadly rounded dorsally. 



History. — The first known species of this genus were described as Antedon valida 

 and A. incerta by Dr. P. H. Carpenter in his report on the comatulids of the Challenger 

 expedition published in 1888. These species were transferred to my new- genus Thalasso- 

 metra upon its establishment in 1907. In my revision of the family Thalassometridae 

 published on January 9, 1909, Antedon incerta and A. valida were included in the list 

 of species I was unable to place satisfactorily. On May 13, 1909, I established the 

 new genus Crotalometra with the genotype C. eupedata, sp. nov., and referred Antedon 

 valida and A. incerta to it, together with Bell's Antedon magnicirra. The generic name 

 Crotalometra had, however, appeared previously in the description of a new species, 

 C. rustica, which thereby became the genotype (see page 92). In 1911 I described 

 Crotalometra propinqua, and in 1912 C. sulcata and C. vera. In my memoir on the 

 crinoids of the Indian Ocean published later in 1912 Crotalometra eupedata, C. propinqua, 

 C. valida, and C. incerta were listed and then synonymies and ranges were given. In a 

 paper on the crinoids of the British Muesum published in 1913, under the heading, 

 "Genus Aglaometra A. H. Clark," I gave notes on Carpenter's specimens of A. valida 

 and .1. incerta. Of these two, A. valida should be taken as the genotype. In my 

 memoir on the unstalked crinoids of the Siboga expedition published in 1918 Aglaometra 

 was included in the key to the genera of the subfamily Thalassometrinae, and Aglao- 

 metra eupedata, A. sulcata, A. valida, A. vera, A. propinqua, and A. incerta were listed. 



KEY TO THE SPECIES IN THE GENUS AGLAOMETRA 



a'. Ossicles of the division series and lower brachials everywhere in close lateral contact, 

 b'. Cirri long and stout, more than half the arm length. 



c 1 . Large and stout; proximal portion of the animal strongly compressed, the lateral profiles 

 from the base of the centrodorsal nearly straight, the two sides making with each other an 

 angle of approximately 45° when the division series are all in contact; arms 100-150 mm. 

 long, cirri 80-90 mm. long with 65-66 segments (from Mindanao to Celebes; 457-1,165 



1?1,264] meters) ..valida (p. 109) 



c'. Somewhat smaller and less stout; proximal portion of the animal broadly rounded, the profiles 

 of the axillaries making with each other an angle of about 90°, but the arms being nearly 

 parallel; arms 00 nun. long, cirri 50 mm. long with 70 segments (Kermadec Islands; 1,152 



meters) incerta (p. 114) 



6 1 . Cirri shorter and more slender, less than half the arm length; arms 130 mm. long, cirri 45-60 



mm. long with 59-69 segments (Philippines and Moluccas; 567-960 meters) .propinqua (p. 116) 



a 1 . Distal angli IBr, an 1 proximal angles of the axillaries and the corresponding angles of the 



first two brachials and of the elements of the first syzygial pair widely cut away, forming large 



and prominent rhombic water pores; the edges of the ossicles bordering these water pores are 



more or less everted and coarsely denticulate, or bear a few coarse spines; arms about 115 mm. 



