506 CLARK: THE CRINOID FAMILY ANTEDONIDAE 



strongly produced and coarsely spinous distal 

 edges (Flores to Borneo and the Philippine Islands; 



0-502 meters) Toxometra 



The cirrus segments have produced distal ends. which 

 overlap the proximal ends of those succeeding; 

 the outer cirrus segments are much longer than 

 their proximal width; the brachials have smooth, 

 or only very finely spinous, distal edges. 

 Smaller, with not over 16 cirrus segments; cirri less 

 numerous, XX-XLV (rarely over XL); arms 

 23 mm. to 50 mm: long (From the Red Sea to 

 Madagascar and Mauritius, eastward to north- 

 ern Australia and the East Indies, and north- 

 ward to southern Japan; 0-106 meters) 



Dorometra 

 Larger, with 16-33 cirrus segments; cirri more nu- 

 merous, XXXV-LX (rarely less than XL); 

 arms 75 mm. to 80 mm. long (Lesser Sunda 

 Islands to the Philippines; 69-140 meters) 



Eumetra 

 P 3 not much the longest and stoutest pinnule on the arm. 

 Pi, P 2 , and P 3 similar and of approximately equal length, 

 with at least 13 segments. 

 Pi, P 2 , and P 3 longer than the genital pinnules; the 

 pinnules are not especially stiffened, and their 

 component segments do not bear prominent 

 spines on the distal edges; the centrodorsal is 

 low hemispherical (Philippine Islands to 

 southern Japan; 23-192 [?250] meters) 



Iridometra 

 Pi, P 2 , and P 3 shorter than the genital pinnules; 

 all the pinnules slender and stiff, especially 

 the lower which are thorn-like with long 

 spines on the distal edges of the segments; 

 the centrodorsal is large, rounded conical 



(Coast of Brazil; 41 meters) Hybometra 



P 2 much longer than Pi, and longer than P 3 , though simi- 

 lar to the latter; centrodorsal more or less sharply 

 conical (Andaman Islands to southern Japan; 54- 

 201 [?250] meters) Andrometra 



Subfamily THYSANOMETRINAE A. H. Clark 

 Key to the Genera of the Subfamily Thysanometrinae 



P 2 with the third segment as long as, or longer than, broad, and the 

 following segments markedly longer than broad (Southern Japan 

 and the Admiralty Islands; 126-355 meters) .... Thysanometra 



