39 



posed of fine muscle fibres. There is no cliitiuous inner 

 lining as in Le peoi)htheirus . Between the basement layer 

 of the intestinal wall and the integnment there is a net- 

 work of muscles passing- in various directions. This 

 tissue represents the body-cavity and body-wall. The 

 spaces between the muscles are filled with the red blood. 

 The peristaltic movement of the intestine is similar to that 

 observed in Lejoeophtheims. 



In the Cyclops stage the mouth leads into a short, 

 narrow oesophagus {ce, Plate V., fig. 2), which 2)asses into 

 the comparatively Avide stomach on its ventral aspect. The 

 stomach is lageniform, with the narrow end pointing 

 posteriorly. On the dorsal aspect, at the anterior end, it 

 is produced into a short, blunt csecum. The narrow end 

 of the stomach connects with the intestine, a long 

 straight narrow tube, greatly compressed over the region 

 of the receptaculum seminis. The intestine terminates 

 ill a very short rectum leading to the anus. The cells 

 both free and attached along the wall of the stomach and 

 intestine are similar to those in the adult. Sometimes 

 the stomach is filled with free cells, which are kept con- 

 stantly travelling backward and forward by the move- 

 ment of the intestine. At other times few free cells can 

 be seen. JS^o trace of blood between the alimentary canal 

 and the integument, as found in the adult, has been 

 observed in the young. 



No trace of a digestive gland could be found in the 

 adult. In the young it is probably represented by a 

 series of groups of cells running along the lateral margins 

 of the cephalo-thorax (Plate V., tigs. 1 and 3, I .v.). A short 

 duct could be traced leading from these groups into the 

 stomach, just posterior to its junction with the oesophag-us. 



When the alimentary canal of a living parasite is 

 opened, and the free cells are isolated and examined with 



