•CLARK] NEW GENERA OF RECENT FREE CRINOIDS 35/ 



lacra naked ; costals rounded, free laterally ; ten to thirty arms, 

 the distichals usually (the palmars always) 2, rarely 4 (34-4); first 

 few brachials discoidal, then quadrate about as long as wide (or 

 slightly wider than long), becoming elongate distally and more or 

 less "dice-box shaped" at the ends of the arms ; distribution of the 

 syzygies irregular; but there is usually one between the third and 

 fourth, second and third, or first and second brachials ; one or more 

 of the lower pinnules usually much enlarged, stout, and stiff, the 

 segments with more or less raised and denticulate distal ends ; distal 

 pinnules moderate, the first two joints short, the others elongate; 

 normally no pinnule on the fourth (/. e., "third") brachial. 



Color in life yellow or white, more or less banded or blotched 

 with purple or red brown ; red-brown ; rarely red, the pinnules yel- 

 low, or entirely red. 



Type of the genus. — Antedon mane a P. H. Carpenter, 1888. 



This genus includes seven small but very interesting species, most 

 of which appear to be rather rare or local in their distribution. Dr. 

 Carpenter placed one species near Antedon milbcrti (overlooking 

 the absence of a pinnule on the fourth brachial), two at the end of 

 the "Milberti group," one (under two specific names) in the "Pal- 

 mata group," and one in the unassigned list at the end of the ten- 

 armed forms. The known species of Cyllomctra are: 



Cyllometra impinnata (P. H. Carpen- Cyllometra manca (P. H. Carpenter) 



ter) " pcrspinosa (P. H. Carpen- 



informis (P. H. Carpenter) ter) 



belli (A. H. Clark) 1 " ruber (A. H. Clark) 



Cyllometra tigrina (A. H. Clark) 



12. PEROMETRA, gen. nov. 



Centro-dorsal conical or hemispherical, usually more or less elon- 

 gate, the cirrus sockets in usually definite vertical rows ; cirri slen- 

 der, long, composed of 35 to 60 segments, the first few short, then 

 elongate until about the middle of the cirrus (or rather beyond), 

 then squarish ; the distal segments bear small dorsal spines ; disk 

 and ambulacra naked ; rays in close apposition, the costals and lower 

 brachials more or less "wall-sided ;" costals united by bifascial artic- 

 ulation ; large, often extravagantly elongated tubercles on the junc- 

 tion of the costals, and of the first two brachials ; always ten arms, 

 the brachials after the fourth quadrate (sometimes triangular), 



1 Cyllometra belli, new name for Antedon loveni Bell, 1884, not Antedon 

 loveni Bell, 1882. 



