Species of British Echinodermata, 107 



in some genera these are wholly absent. Interradial plates of 

 greater or less size always present. 



Genus IV. Ophiothrix, Miiller & Troschel^ 1840. 



Disk not scaly, covered with more or less developed spines 

 and spinose tubercles, and having two very large, triangular 

 radiating scales above the origin of the arms. Arms simple, 

 scaly; superior scales imbricated; lateral carinated, bearing 

 long, elegantly serrated, spreading spines. Interradial plates 

 very small. Oral plates with plain sides. 



Ophiothrix fragilis (0. F. Miiller). 



1789. Asterias fragilis, Miiller, Zool. Dan. vol. iii. p. 28, pi. 98. 



1841. Ophiocoma rosula, Forbes, Brit. Starfishes, p. 60. 



1842. Ophiothrix fragilis, Miill. & Trosch. Syst. der Asteriden, p. 110, 



pi. 9. fig. 2. 

 1845. Ophiothrix rosula, Forbes, Trans. Linn. Soc. vol. xix. p. 151. 

 1841. Ophiocoma minuta, Forbes, Brit. Starfishes, p. 65 {the young). 



Found all round our coast, and ranging from the Mediterra- 

 nean to Norway and Finmark. 



Genus V. Amphiura, Forbes, 1843. 



Disk scaly, generally having six larger scales in the form of 

 a rosette at the centre ; scales smooth, or bearing scattered 

 small spines ; two, usually narrow, radiating scales above the 

 origin of the arms. Arms simple, scaly ; lateral scales cari- 

 nated, bearing simple (or rarely anchor-headed) spreading 

 spines. Interradial plates small. Oral plates with plain sides. 



Amphiura filiformis (0. F. Miiller). 



1841. Ophiocoma filiformis, Forbes, Brit. Starfishes, p. 40. 



1857. Amphiura filiformis, Sars, Bidrag til Kundsk. om Middlehavets 



Litt. Fauna, p. 84. 



1858. Amphiura filiformis, Liitken, Addit. ad hist. Ophiuridarum, Forste 



Afdeling, p. 56, pi. 2. fig. 11. 



Disk covered with small scales, not having any larger than the 

 rest in the centre ; radiating scales narrow, subparallel ; under 

 surface of disk membranous, and nearly devoid of scaly cover- 

 ing. Arms extremely long and very slender : spines 5-7 on 

 each lateral plate ; one of them anchor-headed. No papillary 

 spines over the tentacular pores. 



Shetland; Firth of Clyde; Durham and Northumberland 

 coasts (Norman). '^Killary and other marine loughs of Con- 

 nemara'^ (Forbes). 



Amphiura Chiajii, Forbes. 

 1841. Ophiocoma punctata, Forbes, Brit. Starfishes, p. 37 {the young 1). 



