No. 3] LOXOSOMA DAVENPORTI. 363 



granules which take an intense stain. The third region is what 

 has been described in other species as the liver. This comprises 

 nearly the whole anterior wall of the stomach above the opening 

 of the oesophagus, and is made up of elongated cells containing 

 clusters of coarse granules which in the living condition give 

 a color to the organ, varying in different individuals from yellow 

 to reddish brown. These cells, with the exception of the 

 nuclear chromatin, are but faintly colored by iron-haematoxy- 

 lin, the coarse granules of the cytoplasm remaining unstained. 

 Many cells show conspicuous granular yellow masses in the 

 center of large clear vacuoles, while in the cavity of the 

 stomach similar masses are found which appear to have been 

 discharged from corresponding vacuoles in the liver cells. 



The intestine leads away from the stomach in a course 

 nearly parallel with the oesophagus, when the animal is 

 expanded, and is lined with cilia similar to those of the 

 oesophagus. A slight constriction of the tube marks the 

 passage from the intestine to the rectum. The cilia lining 

 the rectum are the longest present in any portion of the 

 alimentary tract. 



Nervous System. — Further investigation with special nerve 

 methods will be necessary in order to get a knowledge of the 

 details of this system. The brain lies just in front of the 

 intestine and above the stomach, between it and the floor of 

 the atrium, and shows essentially the characters described for 

 several other species of Loxosoma (PI. XXXII, Fig. 7 ; PI. 

 XXXIII, Fig. 27), It is elongated transversely, the two rounded 

 ends being composed of a peripheral layer of cells and an inner 

 fibrous portion continuous with the delicate fibers composing the 

 commissure (PI. XXXIII, Figs. 21, 22, 29, and 30). From each 

 end of the brain two bundles of fibers are given off, but their 

 distribution has not been traced in detail. One on each side 

 passes into the lophophore and extends around parallel with its 

 edge to the median distal region, giving off on the way frequent 

 branches which pass out into the lophophore margin. Sensory 

 bristles are visible upon the tentacles of the living animal as 

 described by Harmer ('85) and others, but their relation to the 

 nerve fibers has not been determined. Fibers, probably nervous. 



