Pomona College, Claremont, California 81 
border of the superior adductor muscles. A large ventral commis- 
sure unites the ganglia under the oesophagus. Each ganglion fur- 
nishes the following nerves: (1) to the adductor inferior muscle, 
a nerve with a little branch to the internal oblique muscle, (2) a 
nerve to the dorsal part of the mantle, (3) a nerve to the ventral 
part of the mantle, (4) a nerve to the arm, (5) branches which join 
with the ventral oesophageal commissure, (6) several nerves form- 
ing the dorsal nerve commissures. The dorsal commissure has 
nerves going to the cirri. 
All nerves are under the skin. Cirri are probably organs of 
touch. 
Heath, 1889, has found sensitive striae formed by high epith- 
elial cells connected with the ganglion cells. These areas are along 
the middle line on the ventral side. 
In spite of fragmentary and conflicting evidence the following 
seems clear as the nervous system of brachiopods: 
A nerve ring surrounds the oesophagus; this is enlarged on 
the dorsal side in a small inconspicuous ganglion near the base of 
the lip. A larger suboesophageal ganglion is the thickening on 
ventral side. The ventral ganglion and perhaps the dorsal retain 
their primitive connections with the surface layer of the skin. Both 
ganglia give off a nerve each side to the arms and along the base 
of the tentacles and lips. The ventral ganglion also gives off nerves 
which supply the dorsal and ventral folds of the mantle and the 
muscles. In some cases the dorsal ganglion seems to be repre- 
sented by a dorsal band only. 
Sense organs are doubtful; the margins of mantle and cirri 
may have a tactile function and the epithelium on the surface of 
the ganglia have been suggested as olfactory areas. 
BIBLIOGRAPHY 
Bemmelen, J. G. Van 
1883. Untersuchungen ueber den Anatomischen und histologishen Bau 
der Brachiopoda Testicardinia. Jen. Zeit. f. Nat. Bd. 16, pp. 88- 
161, pl. 5-6. 
Beyer, H. G. 
1866. A Study of the Structure of Lingula (Glottidia) pyramidata 
Stein. J. H. Univ. Stud. vol. 3, pp. 227-265, pl. 14-17. 
Blockmann, F. 
1892. Ueber die Anatomie und die verwandtschaftlichen Beziehung der 
Brachiopoden. Arch. d. Fren. d. Nar. in Meck. Rost. pp. 37-50. 
1893. Anatomische Untersuchung ueber Brachiopoden. I Crania 
anomala. Bib. Zool. 40, pp. 66, 7 pl. 
Gratiolet, P. 
1857. Etudes Anatomique sur la Terebratule Australe. Jour. de Con- 
cologie. vol. 6, 2 e ser. 2, pp. 209-258, 1 pl. 
