MOLLUSCOIDEA — BRACHIOPODS 



193 



(whence the name from Latin in, not, -\- articulatus , jointed). 

 Intestine ends in an anus ; this in the Lingula group opens 

 laterally between the two valves. 



Lingula (Fig. 75). Basal Ordovician to present. 



Valves thin, almost equal, elongate, tapering towards the 



beak {i.e. tongue-shaped, whence the name from Latin lingula, 



A 



B 



Fig. 75. — Brachiopod movements. A, a Lingula-like shell, Glottidia pyramidata, 

 very abundant upon the shoals of the North Carolina coast, ixposed at low tide. 

 Natural size. i. A characteristic attitude; the sand tube inclosing the pos- 

 terior end of the pedicle is here preserved. 2. Fccces (/.) being extruded from shell. 

 B, Lingula lepidula, very abundant upon the coast of Japan, showing the formation 

 of tubes by the mantle and setae. Through these tubes the water is urged by the 

 cilia lining the brachia, and with the water food is taken in and waste is extruded 

 by the outgoing current. 3. Attitude in sand with setal tubes formed; the 

 brachia show through the transparent shell. 4. Front view of above, c./., anterior 

 folds of mantle ; br., brachia ; s., surface of the sand in which the animal lies half 

 buried. (From Morse.) 



a little tongue). Valves glistening, composed of alternate layers 

 of phosphate of lime and a horn-like substance (ceratin), im- 

 punctate. The animal burrows in the sand by means of the long, 

 slender pedicle which emerges from between the two valves and 



