346 Mary R. Cbavens and Harold Heath, 



clironmtin. Tlie second type of cell is glandular and is usually 

 three or four times the size of the foregoing. In most cases it 

 projects for a considerable distance beneath the bases of the adjacent 

 cells. Each is filled with an abundant coarsely granular secretion 

 which after treatment with haematoxylin has a reddish cast in the 

 earlier stages of its formation but later becomes almost black. The 

 secretion makes its escape, through a slender neck supported between 

 the neighboring cells, in the form of several delicate tlireads. 



Both in external appearance and in the finer histological details 

 the transition from stomach to pylorus is gradual. The latter is 

 dorsoventi-ally compressed between the proboscis sheath and the 

 intestinal .coecum and the epithelial folds, so prominent in the 

 stomach, become almost obliterated, but the lining ciliated and gland 

 cells are essentially the same in both organs. Slightly behind the 

 bases of the cirri (Fig. 10) the intestine communicates with the 

 pylorus whose cells have become slightly lower and relativly free 

 from gland cells. 



The intestine is divided into the following regions: coecum, 

 mid-gut proper and a small terminal section, the rectum (Coe, 1905) 

 or "Enddarm"' (Büeger, 1895). Histologically tliese various sections 

 are of essentially the same general character and in external 

 appearance the distinction is but little marked. The coecum ex- 

 tending from the opening of the pylorus to within a short distance 

 of the brain, is an extensive organ with lateral diverticula which 

 proceed dorsally, keeping on the inner side of the lateral nerves 

 and blood vessels and extend nearly or quite to the mid line. ]\[inor 

 branches in varying numbers and of diverse shapes increase the 

 extent of the primary pouches. 



The transition from the coecum to the intestine is very gradual; 

 in fact the resemblance between the two is so close that there is 

 little more than position to mark the coecum as such. In the mid- 

 gut the spaces between the diverticula are very small (Fig. 5), there 

 being no reproductive glands in this region, and the number of 

 secondary coeca is somewhat greater, but in both the main pouches 

 are directed dorsally to within a short distance of the mid line, and 

 laterally overlapping the lateral nerves and blood vessels extend to 

 the sides of the body. In the tail region (Fig. 9) the primary coeca 

 are smaller and relativly simple, becoming in the more posterior 

 regions little more than small knoblike diverticula. 



The rectum is relativly small but in all of the specimens is a 



