Smith. — Notes on Neiv Zealand Earthworms. 143 



eluded by Claperede in his Olicjochceta Limicolce, has no trace 

 of such a structure. The alimentary canal of Phreodrilus has 

 in other respects the usual simple structure of the lower 

 Oligochceta. It is also, as in the Naidomorpha and Enclnj- 

 trceidce, ciliated throughout, with the exception only of the 

 buccal cavity. The cilia of the pharynx and oesophagus are 

 shorter than those of the intestine, but not less obvious. The 

 buccal cavity is distinguished by the short columnar cells by 

 which it is lined. It is abruptly marked off from the pharynx, 

 particularly on the dorsal side ; the obvious demarcation be- 

 tween the two structures is not, however, due to a sudden 

 change in the character of the cells, but to their very rapid 

 increase in length ; the dorsal wall of the pharynx is lined by 

 very tall cells, which in the space of three or four cells change 

 their character to the comparatively flattened epithelium of the 

 buccal cavity. The posterior limits of the pharynx are not at 

 all clearly marked ; the epithelium very gradually decreases 

 in height, and it is impossible to fix upon any point which 

 might be termed the junction of the pharynx with the 

 oesophagus. The calibre of the intestine is greater than that 

 of the oesophagus, and its walls are in the same way highly 

 vascular. The transition between oesophagus and intestine is 

 not very abrupt ; the intestine seems to commence in seg- 

 ment xiii. 



" Vascular System. — In longitudinal sections of Phreodrilus 

 two perfectly-separate vessels may be observed running along 

 the dorsal wall of the oesophagus. Their course is fairly 

 straight. The two vessels are different from each other in 

 structure, and cannot therefore be confounded in sections 

 where sometimes only one of the two was visible in a par- 

 ticular segment. The vessel, which is closely applied to the 

 dorsal wall of the oesophagus, is extremely thin-walled, and 

 completely filled with coagulated blood. It resembles in these 

 particulars the ventral blood-vessel. In both vessels, par- 

 ticularly in the supra-intestinal, it is easy to see that the 

 blood is a corpusculated fluid ; here and there oval bodies, 

 which have in every respect the appearance of the nuclei in 

 the endothermal lining, may be seen imbedded in the coagu- 

 lated yellow blood. There is little doubt that Lankester's 

 description of corpuscles in the earthworm's blood will be ex- 

 tended to other — to perhaps all the groups of OligocJueta, in 

 many of which they have been observed by Vejdovsky. Here 

 and there the endothelium lining the blood-vessels — particularly 

 at the points where they traverse the intersegmental septals 

 thickened to form valve-like structures. These agglomerations 

 of cells may be the localities where the blood-corpuscles take 

 their origin through the rapid proliferation of the lining mem- 

 brane, as Vejdovsky has suggested. The supra -intestinal 



