ASTEROIDEA 141 



the trawl. It is eaten itself only by other sea-stars {Solaster, 

 Luidia ciliaris). In places it is used for manure (or, at least, 

 formerly was thus used ; teste Forbes). 



A semi-parasitic Copepod, Scottomyzon gihbosum Scott, of 

 the family Asterocheridae, lives on this sea-star. Also another 

 crustacean, Podalirius typicus Kroyer, of the family CapreUidse, 

 is often found on it, though probably not parasitic on it, as is 

 evidently the former. 



The varieties attenuata and gigantea of Hodge can scarcely 

 claim recognition as separate varieties. Likewise the Asterias 

 Murray i ^ of Bell is scarcely anything but a form, hardly distinct 

 enough to be recognised even as a variety, of this very variable 

 species. Possibly also Asterias hispida Pennant belongs rather to 

 this species than to Leptasterias Mulleri. 



In British seas this species is exceedingly common all round 

 the coasts. It is elsewhere distributed from the White Sea and 

 Iceland (but not Greenland) down to the Senegal coast. It is not 

 found in the Mediterranean, except in the oyster basins at Cette, 

 where it has evidently been accidentally introduced. It can stand 

 rather brackish water and therefore may go rather far into the 

 Baltic. Its bathymetrical distribution is from the upper tide- 

 mark down to ca. 400 m., or more exceptionally as much as 

 650 m. 



2. Leptasterias Verrill. 



Differs from the genus Asterias mainly in the dorsal skeleton 

 of arms being somewhat more robust, leaving only small naked 

 spaces, containing each only one or a few papulae. Openings of 

 the genital organs on the ventral side.^ 



1. Leptasterias Mulleri (M. Sars). (Fig. 80.) 



(Syn. Asterias, Asteracanthion Mulleri (M. Sars) ; Asterias 

 hispida Pennant.) 



Rays 5, of medium length, tapering, often somewhat swollen 

 at base and rather distinctly marked off from disk. Adambulacral 

 spines as a rule for some distance on the proximal part of arms 

 in a single series, farther out alternatmg one and two, or some- 

 times only apparently so, alternatingly bending inwards and out- 

 wards. The spines outside the furrow spines (the ventro-lateral 



^ An excellent figure of this Asterias Murrayi is given in Bell's 

 Catalogue Brit. Ech., PI. XII. 1. 



- The openings of the genital organs are as a rule very difficult to observe 

 from the outside, as in most sea-stars. 



