434 



ECHINODERMS OF THE BRITISH ISLES 



tand the right dorso-latoral intcrradius. Calcareous ring consisting 

 of 12 pieces ; the radials perforate. The anchor plates are more 

 or less regular, racquet-shaped, with a narrow handle and usually 

 4 larger central holes in the plate ; the holes are smooth, as is also 

 the edge of the plate. The plates are somewhat smaller in the 

 anterior than in the posterior end of the body. The anchors are 

 ca. 0'3-0-35 mm. long, with arms much diverging ; the arms are 

 serrate. Giant anchors are sometimes found, lying in a regular 

 series in each dorso-lateral interradius ; their arms, which are 



Fig. 266, — Deposits of Labidoplax digitata. x 70. (After Koehler, 

 ^chinodermes, Faune de France.) 



a, Anchor ; b, Anchor plate ; c, Anchor and plate from anterior end of body ; 

 d, Same from about the anterior fourth of body ; e, Giant anchor and plate. 



smooth, are much less diverging than in the usual small anchors. 

 This form of anchor is 0-8-0-9 mm. long, while the plate is only 

 0'3-0'4 mm. long ; the latter differs from the usual plates in 

 having numerous small irregularly arranged holes (Fig. 266). 

 Numerous small oval bodies in the body wall and, especially, in 

 the longitudinal muscles. Colour in life red or brownish, the 

 ventral side lighter. Reaches a length of ca. 30 cm. 



Lives in muddy-sandy bottom, from within tide limits down 

 to ca. 70 m. The larva is a typical Auricularia (Fig. 3, 1), with 

 a few wheels in the postero-lateral lobes. Breeding season in the 



