38 ECHINODERMS OF THE BRITISH ISLES 



1. Trichometra delicata A. H. Clark. (Fig. 23, 1.) 



Cirri very nunierous, with ca. 20-33 segments ; the longer 

 j)roximal segments are ca. 3 times as long as broad in the middle, 

 with the end much widened, partly covering the base of the 

 following joint. The lower brachials strongly convex dorsally 

 and laterally, just in contact with the adjoining ones, but not 

 flattened against them. Arms scarcely reaching a length of 

 40 mm. Colour in life unknown. Pentacrinoid stage unknown. 



In British seas this species has been found only off the W. 

 Coast of Ireland (53° 58' N., 12° 24' W., 382 fms., " Helga "). 

 Elsewhere it is known from off Portugal and S.W. of Iceland. 

 Known bathymetrical distribution, 700-2075 metres. 



1 2 



Fig. 23. — Cirri of Trichometra delicata (1) and Orthometra hihernica (2). x 10. 



Another species, Trichometra ciibensis Pourtales, has been 

 found S. of Iceland and W. of the Faroe Islands and may 

 therefore be expected to occur also off the coasts of Ireland. It 

 differs from Tr. delicata in the lower brachials being only slightly 

 convex dorsally, and sharply and broadly flattened against their 

 neighbours. The arms reach a length up to 65 mm. It is 

 known also from the Western Atlantic, from Cuba to Davis 

 Strait, from depths of ca. 225-2200 metres. 



A third species, TricJiometra minutissima (A. H. Clark), 

 which has been found only off Brazil, 1495 metres, is not likely 

 to occur in British seas. 



6. Orthometra A. H. Clark. 



Differs from Trichometra and Hathrometra in all the cirrus 

 segments being short, the longest not so much as twice as long 

 as the median diameter. The segments are cylindrical ; the 



