HOLOTHURIOIDEA 



417 



though sparsely, granulated, which they are not yet in such young 

 squamatus. The " tail " is, even when completely retracted, 

 discernible by its scales forming a larger number of rings 

 around the anal opening, varying according to the size of the 

 specimen (at 15 mm. length ca. 6 rings), but always distinctly 

 larger than in specimens of a corresponding size of the other 

 species. 



This Holothurian is often eaten by fishes, especially the cod. 

 Also sea-stars, especially large Solasters, devour it. The larva is 

 barrel-shaped, red. Breeding season from March to about mid- 

 summer. 



In British seas this species is known from the north coast of 



F[G. 252 — Calcareous deposits from the ventral sole of Psoitis phantapiis. 

 X 145. (From Danmark's Fauna.) 



Ireland (Blacksod Bay, Down), the west coast of Scotland (Clyde, 

 Firth of Lome), the Shetland Islands, and from Moray Firth and 

 the Northumberland and Yorkshire coast on the east coast. No 

 doubt it will be found all round the coast from the Clyde to 

 Scarborough, and probably somewhat farther south. It is not 

 known from south of the British area, while to the north it goes 

 to the White Sea and Spitzbergen. Also known from Greenland 

 and the American east coast, down to 42° N. Its bathymetrical 

 distribution is from the littoral to 380 m. 



2. Psoitis squamatus Koren. (Fig. 253.) 



(S;yTi. Psolus Fabricii Bell, Massy ; no7i Diiben and Koren.) 



Body very flattened ; anterior and posterior end only very 

 slightly or, when retracted, not at all prominent. Ventral 

 sole very broad, oval, delimited from the dorsal side by a 

 broad, thin, and sharp edge. Tube-feet usually wanting in the 



2 b 



