70 ECHIN0DERM8 OF THE BRITISH ISLES 



2. Luidia ciliaris (Philippi). (Fig. 39, a.) 



(Syn. Luidia fragilissima Forbes ; L. Savignyi Miiller and 

 Troschel.) 



Seven arms, which taper only in the outer part. Three 

 transverse series of lateral papillae correspond to each two 

 marginal paxilla?. Across the dorsal side of arm ca. 10 median 

 paxillse. Lower marginals with 4-5 spines. Papulae many-lobed, 

 lacking only in the outer part of arms. Bivalve pedicellarise on 

 the marginal plates, or trivalve (sometimes also bivalve), on the 

 ventro-lateral plates ; more rarely both sorts of pedicellariae 

 occur. R = 7-8 r. Colour red. It is a magnificent large sea-star, 

 which grows to a size of ca. 30 cm. R. 



It is a very voracious species, the food consisting mainly of 

 various kinds of echinoderms — Ophiothrix, Spatangus purpureus, 

 Echinocardium, Asterias, Thyone, Cucumaria elongata, etc. 

 More rarely it devours mussels (Pecten). Nothing is known to 

 feed on this species. It seems to prefer a sandy bottom. The 

 breeding season is (on the English south coast) in summer-time ; 

 in the Mediterranean, November- January. 



In the British seas it occurs from off the south coast round 

 west to the Shetland Islands, but is not known farther down 

 than off Yorkshire on the North Sea coasts. Otherwise it is 

 distributed from the Faroe Islands to the Cape Verde Islands 

 and the Mediterranean. It does not appear to occur on the 

 Scandinavian coasts. Bathymetrical distribution, 4-ca. 400 m. 



The specimens of Luidia ciliaris from the British seas are 

 stated to differ from those of the Mediterranean in having only 

 trivalve pedicellariae, while the latter have as a rule only bivalve 

 pedicellariae. Because of this difference Ludwig made the 

 British form of this species a separate variety, the var. Normani. 

 'Specimens with both kinds of pedicellariae were, however, after- 

 wards found in the Mediterranean, just as both sorts may be 

 found in British specimens. There is therefore no sufficient 

 reason for maintaining the var. Normani which was also dropped 

 by Ludwig himself, but has been readopted by some recent 

 authors. 



2. Suborder. Notomyota Ludwig. 



Dorsal side covered with paxillae or spines. Marginal plates 

 alternating, covered with spines. Pedicellariae simple or pectinate, 

 rarely bivalvate. Tube-feet with a small sucking disk. A pair 

 of mostly strong dorsal muscles in each arm. 



