EXPLANATION OF PLATES. 45c 



11-13. Lingiila aiiatina, Lam Moluccas. 11, dorsal ; 12, 

 ventral ; 13, A^entral In fig. 11a small portion of 

 the liver and visceral sheath have been removed, to 

 show the course of the stomach and intestine. In 

 some specimens the whole of the viscera, except a 

 portion of the liver, are concealed by the ovaries. 

 In fig. 18 the front half of the ventral mantle-lobe is 

 raised, to show the spiral arms ; the black spot in 

 the centre is the mouth, with its upper and lower 

 lips, one fringed, the other plain. The mantle-fringe 

 has been omitted in figs. 11, 13. a a^ anterior 

 adductors; a', posterior adductor; p jy, external 

 adjusters; p' p' ^ central adjusters; r r, anterior 

 retractors (the anterior occlusors of Hancock) 

 r' r' r', posterior adjusters; c, capsule of pedicle 

 n n, visceral sheath ; o, oesophagus ; s, stomach 

 I, liver ; i, intestine ; y, vent ; 6, branchial vessels 

 m', mantle-margin ; 7?i, inner lamina of mantle- 

 margin retracted, showing bases of settB ; s, setae. . 341 



14. Lingula Murphiana, King. Australia, . . . 341 



