BRACHIOPODA. 



239 



Animal with a highly vascular mantle, fringed with horny setae ; oral 

 arms thick, fleshy, spiral, the spires directed inwards, towards each other; 

 valves opened and closed by sliding muscles. 



Fig. 1G5. Bursal * 106. Venlral. \67. Ventral. 



Lingula anatina, Lam (original). Syn. Patella unguis, L. (part.) 

 a a, anterior adductors; a\ posterior adductor; pp, external protractors ; p'p', cen- 

 tral protiactors; r r, anterior retractors; rW, posterior retractors; c, capsule of 

 pedicle; nn, visceral sheath; o, oesophagus; s, stomach; I, liver; i, intestine; v, 

 vent ; hh, auricles ; h\ left ventricle ; b, branchial vessels ; m\ mantle margin ; m, inner 

 lamina of mantle-margin retracted, showing bases of setae ; s, setse. 



Lingula, Bruguiere. 



Etym. Lingula, a little tongue. Type, L. anatina, PI. XV-. fig. 32. 



Shell oblong, compressed, slightly gaping at each end, truncated in front, 

 rather pointed at the umbones ; dorsal valve rather shorter, with a thickened 

 hinge-margin, and a raised central ridge inside. 



Animal with the mantle-lobes firmly adhering to the shell, and united to 

 the epidermis, their margins distinct, and fringed all round ; branchial veins 

 giving off numerous free, elongated, narrow loops from their inner surfaces ; 

 visceral cavity occupying the posterior half of the shell, and surrounded by a 

 strong muscular sheath ; pedicle elongated, thick ; adductor muscles 3, the 

 posterior pair combined ; two pairs of retractors, the posterior pair unsym- 



* In fig 165 a small portion of the liver and visceral sheath have been removed, to 

 6how the course of the ston;ach and intestine. In some specimens the whole of the 

 viscera, except a portion of the liver, are concealed by the ovari,es. In fig. 167, 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. 165-7. 



Ikl 3 



