8" PROCEEDINGS: BOSTON SOCIETY NATURAL HISTORY. 
The stomach, extending from the hinder end of the esophagus back 
nearly to the posterior end of the animal, is of practically uniform 
diameter throughout. In transverse section it is circular in outline 
but its lumen is not concentric with the external surface owing to 
certain longitudinal thickenings of the inner wall in front. In at 
least one specimen these internal thickenings give the lumen a tri- 
radiate figure in cross section. In the thickened portions the glandu- 
lar cells of the wall are especially abundant. The protoplasm of these 
cells is filled with small deeply staining granules to such an extent 
that it is difficult to make out the cell boundaries, while all through 
the wall arc large vacuoles two or more times the diameter of the nuclei. 
These thickened walls of the stomach are perhaps correlated with the 
absence of a liver which is entirely lacking. Figure 7 (pi. 3) shows 
this part of the stomach in cross section. The blind end behind the 
middle of the body has its wall rather more evenly thickened except 
for an area near the opening into the intestine where it is not thickened 
but is Avell ciliated. 
The intestine, as stated above, begins at about the middle or a 
little behind the middle of the ventral wall of the stomach, -i. c, at 
about the level of the second ciliated band. This portion of the ali- 
mentary canal is of small uniform diameter and is surrounded by longi- 
tudinal and circular muscles. Its inner surface is covered with cilia. 
From its beginning at the stomach it extends in a median and anterior 
direction to the anus, the position of which was described above. 
In the vicinity of the anus are glandular cells which, in the various 
specimens are in different stages of activity. They apparently open 
to the exterior near the osphradium. These cells from their position 
Avould seem to be homologous with the anal gland occurring in various 
molluscs but, so far as I know, not described for the gymnosomatous 
])teropods. 
Nervous System. 
The nervous system in its broader features closely resembles that 
described by Pelsencer ('87) for other gymnosomatous pteropods. 
Paired cerebral, buccal, jiedal, pleural, and visceral ganglia are all 
present. The cerebral and pedal ganglia are of nearly the same 
size; the visceral are about half as large as the cerebral, and the pleural 
are considerably smaller- than the visceral. The small buccal ganglia 
are located in front near the salivary glands. The cerebral ganglia 
