724 BULLETIN 82, UNITED STATES NATIONAL MUSEUM VOLUME 1 



species explicate,, scutifera and dione; this interpretation was followed in the Siboga 

 report in 1918. But of the species assigned at the same tune to the genus Nepiometra 

 I now believe that all but the type, N. laevis, should be placed in the genus Fariometra. 



The treatment of this genus as detailed in the following pages must be regarded as 

 purely provisional because of the paucity and fragmentary condition of the available 

 material in most of the included species. 



[NoTE BY A.M.C.] Following an attempt to summarize the characters of the 

 species of the subfamily Bathymetrinae, I decided that Thaumatometra sokotrae John 

 is more nearly allied to the species of Fariometra with their longer cirri of more numerous 

 segments than to those of the genus in which it was first placed. I have accordingly 

 modified the following key to include sokotrae and at the same time to give less promi- 

 nence to the (somewhat variable) proportions of the centrodorsal in defining the 

 species. Fariometra scutifera and F. obscura have been removed from the key since 

 their cirri and pinnules are unknown, the arms of the type specimens having been 

 broken at the first syzygy. The former is distinguished by having the second brachials 

 unusually long. 



KEY TO THE SPECIES OF FARIOMETRA 



a 1 . Elements of the IBr series with straight, more or less parallel sides, the IB^ not cut away or nar- 

 rowed distally. 



6 1 . Longest cirri with up to 36 segments (Arabian Sea; 2194 meters) sokotrae (p. 725) 



6 2 . Longest cirri with less than 30 segments. 



c 1 . Cirri with 25-28 segments; sides of the IBr series and lower brachials sharply and broadly 



flattened (Philippine Islands; 509-1314 meters). explicata (p. 728) 



c 2 . Cirri with 21-22 segments; sides of the IBr series and lower brachials with projecting spinous 

 patches, not flattened (south of Celebes and north of New Guinea; 1158-1956 meters). 



io (p. 729) 

 a 2 . The sides of the IB^ converging, the lateral angles of the axillaries being produced beyond them to 



define a conspicuous, usually rhombic, pore in each interradius. 

 6'. Longest cirrus segments not more than three times as long as broad. 



c 1 . PI only about two thirds the length of P : ; centrodorsal nearly twice as wide at the base as it is 



high (Maldive area; 797 meters) sewelli (p. 732) 



c 2 . Pj similar in size to, or larger than, P!; centrodorsal only a quarter to a half again as wide at 



the base as it is high.* 

 d l . Peripheral cirri with about 21 segments; PI and P 2 similar in length. 



e 1 . PI with about 16 segments; the two first brachials of each pair of arms not in contact; 

 centrodorsal only a quarter again as wide at the base as it is high (Makassar Strait 



and the Kei Islands; 245-724 meters). dione (p. 734) 



e 2 . Pj with about 21 segments; the first brachials in contact inwardly; centrodorsal about 

 half again as wide at the base as high (south of Lombok, Lesser Sunda Islands; 1097 



meters) nicippe (p. 737) 



<f 2 . Peripheral cirri with about 28 segments; P 2 larger than P] (southeast of Ceram; 204 meters). 



alcyon (p. 736) 



6 2 . Longest cirrus segments five or six times as long as broad (Panama to southern California; 590 

 (?343)-1788 meters).. -- - -- - parvula (p. 738) 



FARIOMETRA SCUTIFERA A. H. Clark 



Fariometra scutifera A. H. CLARK, Journ. Washington Acad. Sci., vol. 7, No. 5, 1917, p. 130 (listed; 



nomen nuduni); Unstalked crinoids of the Szfeoffo-Exped., 1918, p. 248 (in key; range), p. 249 



(detailed description; sta. 119), p. 273 (listed). 

 Fariometra scudifera A. H. CLARK, Unstalked erinoids of the Siboga-Exped., 1918, pi. 24, fig. 93. 



*F. obscura from the Laccadive Islands in 7S6 meters, probably belongs In this section of the key. Its cirri and plnnioles are un- 

 known. It Is dealt with on p. 731 (A.M.C.). 



