EEPOET ON THE ASTEROLDEA. 



195 



b. Adarnbulacral armature with three spines in the second series. 



With an aboral line of spinelets on the infero-marginal plates. 



Actinal spinulation spatulate, obtusely rounded or pointed. 



Lateral spines cylindrical or slightly flattened 



b. Four or five lateral spines in diagonal line. Outer spines of the adarnbulacral 



armature short, not broad nor flaring, placed diagonally. An aboral 



line of spinelets on the infero-marginal plates ..... 



D. With no spinelets on the supero-marginal plates, excepting in some species a very 



small one on the first or first four or five plates in the interbrachial arc. 



a. With small spinelets on the first four or five plates. 



a. With four or five spinelets. A well-developed series of pseudo- 



pedicellarise .......... 



b. With one spine only, on the first plate. No pedicellarioe , 



b. With no spines whatever on the supero-marginal plates. 



a. One lateral spine. 



a. With two or three spines in the second series of the adarn- 

 bulacral armature. 

 i. Supero-marginal plates broad, with small granules. 

 Paxilloe with five to eight granules (or spine- 

 lets) on the central tabulum .... 



ii. Supero-marginal plates narrow, with large granules. 

 Paxillaa with one granule on the central 

 tabulum ........ 



6. Lateral spines two, side by side. Infero-marginal plates covered 

 with squamules. An aboral line of spinelets present. Lateral 

 spines taper and pointed. Supero-marginal plates very broad . 



c. Lateral spines four, in an oblique line. Spines of the adarnbulacral 



armature all cylindrical and taper. Infero-marginal plates with 

 papilliform spinelets rather than squamules. No aboral line of 

 spinelets. Supero-marginal plates not very broad . . 



irregularis, i 

 pontoporxiis. 



zebra, 

 velitaris. 



granulatus 



monacanthus. 



ciiigulatus. 



mesactus. 



Chorology of the Genus Astropecten. 

 a. Geographical distribution : — 



Atlantic : Twenty-two species between the parallels of 70° N. and 40° S. 



On the eastern side : Astropecten irregularis, off the coasts of 

 Scandinavia and Britain ; and in the Mediterranean (fide Marion). 

 Astropecten serratus, off the west coast of France (this species is also 

 reputed to be a Mediterranean form, but its claim to be so considered 

 appears to be doubtful). Astropecten aurantiacus, Astropecten bispi- 

 nosus, Astropecten jonstoni ( = Astropecten squamatus, M. and T.), 

 Astropecten pentacanthus, Astropecten platyacanthus, and Astro- 

 pecten spinidosus, in the Mediterranean. Astropecten aurantiacus also 

 extends to the Canary Islands. * Astropecten herinatophilus, off the 



