THE IRISH SKA. 125 



been better investigated, it is probable the mode of inser- 

 tion of the brachial scales will assume a generic, or at least 

 subgeneric, importance. 



1. OPHIUBA. Linn. ; Agassiz. — Baj/s simple, squa- 

 mose, prolonged into the disk superiorly, and separated 

 at their origins beneath by large fiddle-shaped plates. 

 Brachial spines appressed. 



Two species of this genus, which is restricted to the la- 

 certose Ophiura?, are found in the Irish Sea. One only is 

 recorded by British authors, and the two I here describe, 

 though very distinct, have probably been hitherto con- 

 founded, both on the continent and at home. 



1. Ophiura texturata.* — PI. IV. Fig. 3, 4. 



Disk imbricated above by smooth unequal scales, those of the 

 centre very small and rosulate ; two large scales with diverging 

 apices at the base of each ray ; pectinated scales clasping the base of 

 the rays laterally with "above twenty teeth, Intermediate inferior 

 plates hollowed out at the sides. Rays covered superiorly by trans- 

 versely-oblong, narrow plates, beneath by ovate plates. Sides, 

 with lateral plates, bearing about seven short, blunt, appressed 

 spines on their superior margins. Rays not three times as long as 

 the breadth of disk. The disk of the largest specimen I have taken 

 is nine-tenths of an inch broad. 



Rare in the Irish Sea ; dredged off Douglas, Isle of Man. Appa- 

 rently frequent on the east coast of Scotland. Colour either brown 

 or flesh-colour. 



2. Ophiura albida,-|- Forbes. — PI. IV. Fig. 5, 6. 



Disk imbricated above by smooth unequal scales, a large one in the 

 centre, surrounded by five others of the same size ; two quadrangu- 



" Lamarck, v. ii. p. 542, Asterias ophiura, Linn. Asterias lacertosa, Penn. 

 Brit. Zool. 4, 130, pi. 34, fig. 1. Ophiura brachiata, Fleming, p. 488. Stel- 

 la lacertosa. Link, p. 2, No. 4 ; Johnston in Mag. Nat. Hist. vol. viii. p. 46'5, 

 fig. 41. O. aurora, Risso, vol. v. p. 273, fig. 29. 



+ An Ophiura le.rluruta. 2. Eadem minor albida, Lamarck, vol. ii. 

 p. 542 ? 



