OF CONCHOLOGY. 



155 



more produced and pointed than the other. Surface smooth or 

 concentrically striated, covered with a thin epidermis. Brachia 

 elongated, subspiral, situated on each side of tlie mouth, exter- 

 nally -ciliated. The muscular impressions are light ; close to the 

 beak is one formed by the post adductor, two others {adductores 

 anteriores) are seen near the middle of the shell ; they are di- 

 vided in the neural valve by a blunt projection, and in the hi'emal 

 valve by a mesial ridge. In the neural valve another triangular 

 depression just before the last mentioned, indicates the seat of 

 the insertion of the anterior retractors. 



Horny laminae of the shell permeated by excessively minute 

 tubuli. 



Fig. 35. Haemal view of animal of Lingula a7iatina, after "Woodward. 



Figs. 36, 37. Neural views of same, aa, anterior adductors ; «', post ad- 

 ductor ; pp, external protractors ; p^p^, central protractors ; c, capsule of ped- 

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

 V, vent; ?«, mantle-margin; s, setie ; b, pallial sinuses and their branches. 



T^j^e. Lingula andtma, Lam., Anim. sans Vert. vol. vii, 

 p. 390. 



Jlab. Moluccas and Philippines. 



The peduncle of Lingida is not a simple means of attachment 

 alone as in the cirrMpedes, but is mobile and muscular ; the 

 animal when detached from its position is able to move it rapidly 

 about, like an arm or fin, and, when attached, by using its sup- 

 port as a fulcrum it can move the shell in various directions with 

 great facility. The}'- prefer sandy or muddy bottoms, into which 

 they would appear to be able to burrow with their peduncle, and 

 remain with only the anterior edge of the valves at the surface 

 of the sand. They are frequently entirely unattached. 



