Species of British Echinodermata, 119 



locality, though there can be little doubt that it will be found 

 hereafter among the Hebrides. 



Fam. II. Solastridae. 



A special anal opening, situated in the centre of the aboral 

 disk. Two rows of ambulacral tentacula. 



Genus XII. Archaster, Miiller & Troschel, 1840. 



Disk,- together with the five moderately long rays, flat above, 

 and covered in every part by closely aggregated paxillse. Two 

 rows of large lateral plates, the upper covered with large gra- 

 nules or mamillary spines ; the lower covered with closely ap- 

 pressed, short, papillose spines. Suckers biserial. Anus central. 

 Pincer-formed pedicellarise present. Respiratory pores isolated 

 among the paxillse. 



Archaster Parelii (Diiben & Koren). 



1/68. Asterias aurantiaca, var., Parelius, Kongelige Norske Videnskabers 

 Selskabs Schrifter, Act. Nidross. iv. p. 325, pi. xiv. figs. 3, 4. 



1844. Astropecten Parelii, Diiben & Koren, Skand. Echin. p. 247, pi. vii. 

 figs. 14-16. 



1861. Archaster Parelii, Sars, Oversigt af Norges Echinodermer, p. 35. 



Greater to lesser radius as 3 to 1. Aboral surface entirely 

 covered with closely aggregated paxillse. Each of these 

 paxillse consists of a pillar, widening above and supporting 

 about twenty-five (15-30) mamillary spines of different sizes. 

 Madreporiform tubercle nearer to the centre than to the mar- 

 gin of the disk, minute, not so large as one of the paxillse. 

 Lateral ray-plates thirty, oblong, entirely covered with mamil- 

 lary spines of the same kind but larger than those of the 

 paxillse, nearly a hundred on each plate. Oral surface entirely 

 covered with closely packed short papillose spines. The infe- 

 rior lateral plates are most beautiful cushions of closely aggre- 

 gated, appressed papillary spines, each plate having a central 

 row of 3-5 rather larger and more conspicuous spines, which, 

 however, like all the rest, are closely appressed to the surface. 

 Indeed there are no spines projecting conspicuously beyond 

 the rest from any part of the body. The spines of the adam- 

 bulacral plates are so numerous that, spreading from them in 

 all directions, they nearly choke up the ambulacral channels. 

 Greater diameter not quite 4 inches. 



A single specimen of Archaster Parelii was dredged by Messrs. 

 Jeffreys and Waller, during the past summer, on the Outer 

 Haaf, off" Shetland, in 100 fathoms. It is a very interesting 

 addition to our list of British Echinodermata. I have removed 

 this species from the genus Astropecten, in which it had been 



