Tlvo New Species of Ch<ietog«ister. 95 



Segmentation. 



Segmentation is marked externally by the setae, internally by the 

 septa, nephridia and ganglia of the ventral nerve cord. The number 

 of segments varies; the individuals I observed consisted of frf)m 

 16 to 25 segments. 



Setae. 



The setae of the fii-st bundle are longer than those of the others. 

 Each seta is of the same general shape as in C. australis, but is 

 much longer in comparison to the difference in the size of the animals, 

 and the forked end is much shorter. There are also fewer in each 

 bundle than in C. australis. 



Body Cavity. 



Tlie body cavity is divided by the septa into segments. Tlie 

 septa are more clearly distinguished towards the anterior end. The 

 first septum is behind tlie pharynx, the second behind the oesophagus, 

 the sixtli l)e]iind tlie crop, the ninth beliind the stomach. (Fig. ii.) 



Alitneiitary Canal. 



The mouth (Fig. ii. M.) is large and circular; it is situated on the 

 ventral surface, and opens into the buccal cavity (Fig. ii. B.C.), 

 which leads to the pharynx. (Fig. ii. P.) 



The pharynx is extremely muscular, and is attached to the body 

 wall by muscle bands. 



The oesophagus (Fig. ii. 0.) is short and narrow, and leads into 

 a large, thin walled sac, the crop (Fig. ii. C), the walls of which 

 appear to be only one cell thick. 



A well-marked constriction separates the crop and stomach. 



The stomach (Fig. ii. S.), lying in the seventh, eighth, and ninth 

 segments, is l)etter defined than in G. australis: it is a dilatation of 

 the alimentary canal not so wide as the crop, and narrowing pos- 

 teriorly to pass into the intestine (Fig. ii. I.), which I'uns to the 

 anus. 



Circulatory System. 



The blood is colourless, and has no corpuscles. The course of the 

 blood vessels is similar to that in C. Australis. 



Excretory System. 

 The excretory system consists of a number of paired nephridia, 

 and there are typically a pair of those in each segment. (Fig. ii. 

 N.) They generally commence in about the seventh segment, being 



