ASTEROIDEA 57 



Johnstoni Delle Chiaje (Syn. A. scjuamatus Miill. and Troschel) 

 from the North Sea, off Fohr.) Another species, A. hermatophihis 

 Shiden, is known onl\^ from the Azores (ca. 800 m.). While there 

 may perhaps be a possibility that the latter may occur also as 

 far north as the British seas, it is hardly to be expected that 

 any of the other species will be found there. It may therefore 

 suffice in regard to these forms to refer to the descriptions 

 and keys of the European species of Astropecten given by 

 Koehler in Faune de France, i. Echinodermes (1921) ; and Les 

 Eckinodermes d' Europe, i. 1924, p. 187. A. hermatophilus is 

 distinguished from irregularis, to which it has otherwise great 

 resemblance, by its marginal spines, only three on each 

 lower marginal, the U]3per one of which is the largest, while in 

 irregularis, with 4-5 marginal spines, the second or third from 

 above is the largest, one or two smaller spines being found above, 

 adoralh' to, the largest. 



Key to the species of Astropecten of the British seas. 

 Oral interradial areas with onh^ one series of plates ; lower marginals 



simply flattened . . . . I. A. irregularis {Venn.) 



Oral interradial areas with 2-3 series of plates ; lower marginals 



elevated, wedge-shaped . . 2. A. sphenoplax Bell 



1. Astropecten irregularis (Pennant). (Fig. 32.) 



(Syn. Astropecten Mi'dleri Miill. and Troschel; A. acicularis 

 Norman ; ^4. ibericus Perrier.) 



Upper marginal plates general^ with a larger, conical spine, 

 especially in the outer part of arms. Lower marginals flattened, 

 rectangular, at their upper end with 4-5 large marginal spines in 

 an oblic{ue series that passes downwards along the outer edge of 

 the plate ; the second-third from above is the largest, one or two 

 smaller ones being found adorally above the largest, the plates 

 otherwise covered with small flattened, somewhat scale-like 

 spines. Upper and lower marginals corresponding exactly to 

 each other. Oral interradial areas with a single series of plates 

 (the ventrolateral plates), mostly 4-7 in number. In larger 

 specimens there may be indications also of a second (outer) series. 

 Adambulacrals with 3 ecj[ual-sized furrow sjoines. No joedicellariae. 

 Colour reddish-violet or yellowish, with or without j^urple marks. 

 R = 3-5-4-5 r. Grows to a size of ca. 10 cm. R. 



The great variation in the development of spines on the upper 

 marginal plates has caused the establishment of some '" species " 

 which cannot, however, rank higher than varieties, viz. var. 



