148 ZOOLOGY. 
the anterior part of the body of Lingula. The mouth is 
bordered by two membranous, highly sensitive and movable 
lips. The stomach is a simple dilatation of the alimentary 
canal, into which empty the short ducts of the liver, which 
; is composed of 
massesof cceca. 
The liver origi- 
nally arises as 
two diverticula 
or offshoots of 
the stomach. 
The short in- 
testine ends in 
a blind sac or 
i . 4 in a vent, and 
st @ _& mo Of r is, with the 
Fig. 98. —Longitudinal section of the anterior portion of 
Lingula. m, mouth; ©, esophagus ; st, stomach; @, arm; ci, stomach, freely 
cirri; 3f, brachia] fold; cb, cartilaginous base of arm; s, : 
sinus iaiten to the arm ; cc, cephalle collar or pallial mem- suspended in 
brane.~-After Moree. th eperivisceral 
cavity by delicate membranes springing from the walls of the 
body. (Fig. 99.) In those Brachiopods allied to Terebra- 
tula, Terebratulina, Thecidium, Waldheimia, Rhynchonella,. 
etc., the stomach ends in a blind sac, and there is no vent, 
the rejectamenta escaping from the mouth. In Lingula and 
Discina there is a vent which terminates anteriorly on the 
right-side. In Lingula 
the intestine makes a 
few turns, while in Dis- 
cina it makes a single 
turn to the right. 
The nervous system 
consists of two small 
3 Fig. 99.—Transverse section of Lingula, 0, 
ganglia above, and an_ bands suspending the intestine in the perivisce- 
; s ral cavity ; 4, intestine ; *, segmental organ ; 0, 
infracsophageal pair of ovaries; 7, liver; g, gills; se, setee.—After 
larger ganglia, and there Morse. 
are two elongated ganglia behind the arms, from which nerves. 
are given off to the dorsal or anterior lobe of the mantle. 
From the infracesophageal ganglia two lateral ventral cords. 
pass backwards, in their tract sending off delicate threads, 
