122 Rev. A. M. Norman on the Genera and 



the former, but the function may in some degree be that of the 

 latter; and these arching spines are perhaps employed as im- 

 perfect instruments of prehension. 



This species is, for the most part, a southern form ; but it is 

 met with here and there on the western shores of Great Britain, 

 and attains its northern limit on the coast of Rosshire, where it 

 was found by Professor Edward Forbes. It appears to be entirely 

 absent on the east coast. 



Genus XV. Sol aster, Forbes. 

 [Solaster, Forbes, 1839. Crossaster, Miiller & Troschel, 1840.] 

 Body convex, covered above and below with paxillse. Rays 

 8-14, long, rounded above. No marginal plates or rows of 

 spines edging the disk and arms. Respiratory pores very nume- 

 rous, everywhere situated between the paxillse. Suckers biserial. 

 No pedicellarise. Anus central. Madreporiform tubercle mid- 

 way between the centre and the margin of the disk. 



Solaster papposus (Linnseus). 

 Solaster papposa, Forbes, British Starfishes, p. 112. 



Everywhere round our coasts. Not known to the south of 

 Great Britain ; but extending northwards to Scandinavia, Fin- 

 .mark, Iceland, Greenland, and western North America. 



Solaster endeca (Linnseus). 

 Solaster endeca, Forbes, British Starfishes, p. 109. 



With similar British and exotic range to the last ; but not so 

 abundant, and an inhabitant of deeper water, never occurring 

 between tide-marks. 



Genus XVI. Porania, Gray. 



[Goniaster, Agassiz, 1857 (partly). Porania, Gray, 1841. Asteropsis, 

 MuUer & Troschel, 1842.] 



Body pentagonal, very convex and tumid above, flat beneath. 

 Rays very short. Oral surface composed of elegantly tessellated 

 plates. Aboral surface composed of similar but less regular 

 plates, and covered, when alive, with a thick and highly lubri- 

 cated membrane. No spines, or paxillse, or pedicellarise, except 

 that a circlet of small spines closes over the anal opening, 

 which is central, and that the sharp edge of the disk and rays 

 is fringed with a row of spines arranged in single file. Respira- 

 tory pores very numerous, in groups. Suckers biserial. Madre- 

 poriform tubercle midway between the centre and the margin of 

 the disk. 



Porania pulvillus (0. F. Miiller). 

 1788. Asterias pulvillus, Miiller, Zool. Dan. vol. i. p. 19, pi. xix.figs. 1,2. 



