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



Astropecten irregularis (Pennant). 



1776. Asterias aurantiaca, Miiller, Zool. Dan. Prod. p. 234, no. 2831 (but 



not of Linnteus). 



1777. Asterias irregularis, Pennant, Brit. Zool. vol. iv. p. 61. no. 47. 

 1841. Asterias aurantiaca, Forbes, Brit. Starfishes, p. 130. 



1844. Astropecten Mulleri, Miiller & Troschel, Archivfur Naturgeschichte, 

 vol. x. p. 181. 



1844. Astropecten echinulatus, Miiller & Troschel, Archiv fur Natur- 

 geschichte, vol. x. p. 181 {fide Sars). 



Marginal plates 20-40. Greater to lesser radius as 4-6 to 1. 

 Spines of the under surface flattened, spatulate, widening at 

 the tips. Each inferior marginal plate bears one transverse row 

 of spines, which exceed the rest in length, and themselves 

 gradually increase in size towards the superior margin of the 

 plates. 



Common all round the coasts of Great Britain, and found in 

 Scandinavia. My largest specimen measures 6 inches in dia- 

 meter. 



Astropecten acicularis, n. sp. 



Marginal plates 20-23. Greater to lesser radius as 3-4 to 1. 

 Spines of the under surface aciculate (not spatulate or 

 widening at the tips), and only the large spines of the infe- 

 rior marginal plates slightly flattened. Inferior marginal 

 plates with two transverse rows of larger spines, which gra- 

 dually increase in length towards the superior margin of the 

 plates. 2 inches in diameter, from tip to tip of the rays. 



This species resembles the last closely in every particular with 

 respect to the aboral surface, but differs greatly in the character 

 of the spiny armature of the inferior portion of the body. The 

 rays are rather shorter than is usual in A. irregularis. The 

 three innermost spines of the adambulacral plates (of which the 

 central is the longest, and curved, and all are cylindrical) are pro- 

 jected over the ambulacra. All the spines of the under surface 

 are slender and pointed, and thus differ widely from the 

 flattened, widening spines of A. irregularis. The inferior mar- 

 ginal plates, instead of being covered, as in A. irregularis, with a 

 cushion of closely appressed, short, broadly flattened spines, and 

 a single transverse row of much larger and conspicuous spines 

 (generally, though not always, greatly flattened), are furnished 

 with cylindrical slender spines of various lengths, from among 

 which the chief row does not stand out so conspicuously. 



Astropecten acicularis was dredged by me in 1861, in company 

 with Messrs. Jeffreys and Waller, on the Outer Haaf at Shetland, 

 living gregariously in 80-100 fathoms. It does not appear to 

 agree with any of the numerous species of this genus which have 

 hitherto been described. 



