ASTEROIDEA 67 



It is a small form, scarcely reaching more than 30 mm. R. 

 Biology and development unknown. 



In British seas this sj)ecies has been found in the Faroe 

 Channel (" Porcupine ") and S. of Ireland (48° 31' N., 10° W.). 

 Elsewhere it has been found at the Scandinavian coasts from 

 Finmark to Trondhjem Fjord on the coasts of Norway, as also at 

 West Greenland and the American east coast, down to 38° N. 

 Further it occurs in the North Pacific from the Bering Sea 

 down to northern Japan. It may then well be supposed to be 

 circumpolar. Bathy metrical distribution ca. 40-1260 m.^ 



III. Family LuiDiiDiE 



Upper marginal plates replaced by paxilla? ; lower marginals 

 well developed, covered with spines. Aboral side with paxillae ; 

 oral interradial areas with spines. No cribriform organs ; 

 marginal fascioles never w^ebbed. No intestine, intestinal caeca 

 or anus. Tube-feet without sucking disks. Ampullae double ; 

 pa23ula3 bush -shaped. Genital organs in a series along each side 

 of arm, almost to the end. 



Only one genus in European seas. 



1. Luidia Forbes. 



Arms long and narrow ; disk small, flat. Lower marginals 

 very broad, with some large, projecting spines. Oral interradial 

 areas small. Simple pedicellarise may occur. 



Only two species are found in British and European seas ; a 

 third species, Luidia africana Sladen, occurs on the N.W. coast 

 of Morocco, but there is hardly any prospect of finding it as far 

 north as the British seas. It is closely related to L. Sarsi, but 

 grows to a larger size, ca. 20 cm. R. 



The British species are both very fragile, especially L. ciliaris, 

 and it is rather difficult to secure complete specimens ; if it is 

 grasped hj one of its arms this almost instantaneously breaks 

 off.2 In good accordance herewith the regenerating power is 

 very great, and most specimens show one or more arms in 

 regeneration. 



^ The statement (Bell, Catalogue Brit. EchinodermSy p. 66) that it was 

 taken at a depth of 1312 fathoms (2470 m.) in the Faroe Channel (" Porcu- 

 pine ", St. 82) is simply a misprint for 312 fathoms. 



2 An amusing account by E. Forbes of his vain'efforts to secure a fine 

 specimen of " Luidia fragilissima " is quoted in G. H. Lewes's Sea-side 

 Studies, 2nd ed., 1860, p. 255. 



