124 MR FORBES ON THE ASTER JAD^5 OF 



It is strange that this, the largest and most remarkable 

 of all the British star- fishes, should so long have remained 

 unnoticed, and still stranger that when first described it 

 should have been referre*d to Stellonia rubens, and with a 

 query to Asterias hispida and Asterias spinosus. Its 

 claim to rank as the type of a separate genus cannot be 

 doubted ; for by no stretch of character can it be united with 

 any of the preceding. Its wonderful power of not only 

 casting off its arms entire, but breaking them voluntarily 

 into little pieces, with great rapidity, and with quite as 

 much facility as an Ophiura, has defeated all my attempts 

 to preserve a specimen entire. It is rare ; but I have 

 taken it several times in deep water on the Manx coast. 

 Dr Johnston obtained it at Berwick-on-Tweed. 



I have named my genus after Luid, one of the earliest 

 and most judicious observers of the British Radiata. 



FAMILY II. OPHIURA. 



In the second family of Asteriadae, Professor Agassiz in- 

 cludes those star-fishes which have hitherto been arranged 

 under the genera Ophiura and Euryale. It seems to me 

 that the latter should form a separate family. The recent 

 species of Ophiura he arranges under two genera, Ophi- 

 ura and Ophiocoma, separating them on the ground of 

 the different forms of the brachial spines. On examining 

 our British species, however, I am convinced that this is 

 but a secondary character, and can scarcely be regarded 

 as a true ground of generic distinction. The two genera 

 are most natural, and good permanent characters may 

 be derived from the mode of insertion of the arms, and 

 the form of the five scales or plates which separate their 

 origins beneath. When the species of Ophiurae shall have 



