290 WILLIAM A. HASWELL. 



each of those divides both externally and internally into two 

 or three parts ; internally, these pass into the internal layer, in 

 which they are traceable for a little distance as vertical lines ; 

 externally, they are affixed to the most external layer. Between 

 the radiating fibres, which are not closely placed, is a finely 

 fibrous material, which is little acted on by staining agents, and 

 embedded in this, here and there, is a large ganglion-cell. 

 Besides these radiating fibres the wall of the organ comprises 

 four layers of circularly arranged fibres; the most internal 

 layer (i. c. I.) is longitudinal in direction, the second and third 

 (e. c. t. and i. c. t.) transverse, and the fourth (most external 

 e. c. I.) longitudinal. 



The intestine (Plate XXI, fig. 5) is a wide, dorso-ven- 

 trally compressed sac of rectangular outline, nearly as broad 

 as long, which occupies about the middle third of the length of 

 the body and more than half its breath. It is surrounded on 

 all sides, and to some extent also in front and behind, by the 

 rounded lobes of the vitelline glands ; in the middle in front it 

 comes into relation with the pharynx, while behind the recepta- 

 culum seminis and ovary lie in the concavity of a sort of recess 

 between two very slight postero-lateral prolongations. 



The walls of the intestine are deeply sacculated, a number 

 of incomplete partitions running inwards from the body wall, 

 as already described, and producing a series of circular con- 

 strictions, so that the internal cavity consists of a central 

 space and a series of annular cseca lying between successive 

 constrictions. 



The intestinal wall (Plate XXI, fig. 7) is of considerable 

 thickness. It is composed of greatly elongated epithelial cells 

 (e.) with rounded inner ends which are devoid of cilia. In the 

 granular substance of the cells themselves, as well as in little 

 special reservoirs (c), which appear to be intracellular, are 

 very numerous large granules which show a distinct concentric 

 structure ; these, which colour darkly with hematoxylin, but 

 are little affected by carmine, are most numerous towards the 

 bases of the cells. This epithelium is supported externally by 

 a thin musclar coat (m.). 



