ASTEROIDEA 117 



In British seas this species is known only from the cold area 

 of the Faroe Channel ('"' Porcupine ", '' Michael Sars "), and 

 from the Lousy Bank. It is known elsewhere from off Stavanger 

 on the Norwegian coast to Spitzbergen and the Siberian Sea, 

 and from Greenland to 40° N. on the American coast. The 

 North Pacific forms L. fiircilliger Fisher and L. vexator Fisher 

 are scarcely specifically distinct from the Atlantic form. Bathy- 

 metrical distribution ca. 30-1350 m. 



VI. Family Echinasterid^ 



Disk very small ; arms five, long, slender, cylindrical, with 

 no distinct limit between dorsal and oral side. Dorsal skeleton 

 reticulate ; spines single or in small groups, not in the shape of 

 paxillae. No pedicellariae. Tube-feet in two series. 



Only one genus known from the British seas ; but another, 

 Echinaster, is likely to be found off the south coast, the single 

 European species of this genus, Echinaster sepositus (Retzius), 

 occurring as far north as Brittany (Roscoff) (otherwise distributed 

 as far south as Cape Verde ; very common in the Mediterranean ; 

 bathymetrical distribution : from the coast down to 1060 m.). 



Key to the genera of Echinaster idee known from or likely to 

 occur in the British seas. 



Spines very fine, generally in small groups ; papulae also on the 

 oral side . . . . . . 1. Henricia Gray 



Spines rather coarse, single ; no papulae on the oral side 



Echinaster Miill. and Troschel 



1. Henricia Gray. 



(Syn. Cribrella Liitken ; Cribella Forbes (non L. Agassiz) ; 

 Magdalenaster Koehler.) 



Dorsal skeleton bearing numerous small spinelets either in 

 groups or scattered along the ridges composing the reticulate 

 skeleton. Marginal plates more or less distinguishable. Adam- 

 bulacral plates with one or more spinelets placed deep within 

 the narrow ambulacral furrow. Papulae numerous, occurring 

 also on the oral side. 



Two species are known from the British seas, but three more 

 may be expected to occur there also, viz. Henricia biscayensis 

 (Koehler) (Bay of Biscay, 1410 metres ; only a single specimen 

 known, taken by the " Caudan ") ; Henricia caudani (Koehler) 

 (Bay of Biscay, 650 metres ; only a single specimen known, 



