STRUCTURE OF BRACHIOPODS. 149 
but with no ganglionic enlargements, except in Discina, 
where they terminate each by a ganglion in the last two 
posterior muscles. Morse has discovered the presence of 
auditory capsules in Lingula. 
Respiration is mainly carried on in the mantle (pallial 
membrane). In Lingula the pallial membrane is divided 
into oblique transverse sinuses, which 
ae run parallel to each other. From 
ARPA N these arise, says Morse, numerous 
au flattened ampulle, which are highly 
Fig, 100.—Ampnlie of blood contractile. The blood courses in 
ginures. showing cource taken regular order up and down these 
yy the e. 7 : 
sinuses, entering each of the ampullz 
in turn, Fig. 100 represents a row of five ampulle with in- 
dications of the course taken by the blood-disks. These 
ampulle have not been found in Discina, though the pallial 
sinuses are very prominent. The breathing process is also. 
carried on in the tentacles or cirri. 
Intimately connected with the vascular system is a gland- 
ular portion of the tubular part of the segmental organs ot 
the Brachiopoda, which is 
supposed to represent simi- 
Jar parts in worms as well 
as the glandular, excretory 
portion of the organ of 
Bojanus in mollusks, and is 
supposed to be depuratory 
or renal in function. 
The reproductive system 
of Brachiopoda consists of 
ovaries, oviducts or seg- 
mental organs, Fig. 101, ,Af D'pSagmonyslsoranns of, Broo. 
and spermaries. The sexes More: 
are probably separate in all Brachiopoda (Morse). 
The ovaries are attached in Discina and Lingula to the 
delicate vascular membranes of the large sinuses in the pal- 
lial membranes, the vascular membranes being thrown into. 
conspicuous ruffs when the eggs are ripe. In Terebratulina. 
and Rhbynchonella they are not only similarly situated, but. 
