92 Olive B. JDavies: 



The stomach (Fig. i. S.) is marked off from the crop by a very 

 definite constriction. The stomach and intestine (Fig. i. I.) are not 

 clearly distinguishable in prepared specimens, but in the living 

 animal the stomach can be distinguished by its refractive particles. 

 Their walls are more muscular than those of the crop, and the 

 lumen miich smaller owing partly to the greater development of tlie 

 lining cells. These cells are not nearly so distinct as in the crop, 

 and their nuclei are not so clear. The stomach occupies the seventh 

 and eighth segments, and the intestine runs from this to the 

 posterioi^end, where the anus opens to the exterior. 



Circiilnfn nj .S' y .s f e m . 



The blood is colourless and has no corpuscles. There is a distinct 

 dorsal contractile vessel running from behind forwards; its pulsa- 

 tions are very noticeable j\ist about the junction of the oesophagus 

 and the crop. Here it appears to form a dilatation, and a little 

 in front of this a vessel runs down either side of the oesophagus, and 

 the two unite to form a ventral vessel. 



Ex ere to nj Si/s teni . 



The excretory system consists of paired nephridia. They are con- 

 stantly found in the seventh and eighth segments (Fig.i. N.), and 

 often in the tenth and eleventh, and sometimes immature ones more 

 posterior still. They are not found in the newly-formed segments. 

 The openings of the nephridia to the exterior are situated imme- 

 diately in front of the bundle of setae of the same segment. Follow- 

 ing back from the opening to the exterior, is a diverticulum, and 

 beyond this a dilatation, then follows a coiled tube, which ends in 

 a swelling near to the anterior septum of the segment, to which it 

 seems to be attached by muscle fibres. (Fig. vii. A.) 



Nervous St/sfem. 



The nervous system consists of a dorsal cerebral ganglion (Fig. i. 

 C.G.) ; from this nerve conmiissures run round either side of the 

 alimentary canal to a ventral ganglion. Running from this there 

 is, typically, a ventral nerve cord (Fig. i., N.C.), with a ganglion 

 in each segment; but in the anterior segments the nerve cord is 

 double; and in the asetigerous portion the ganglia somewhat irregu- 

 lar and ill-defined. 



