STUDIES ON EARTHWORMS. 565 



that of other earth-worms, with the exception of Poutodri- 

 lus/ in the absence of a gizzard. 



The pharynx extends to the hinder boundary of somite iv 

 (fig. 14), the walls are very muscular, and the usual radiating 

 muscles pass to the body wall, some going as far back as somite 

 VI. In transverse sections I found numerous glandular-looking 

 cells amongst the muscles of the dorsal and lateral wall, but I 

 was unable to find any duct leading to the lumen of the 

 pharynx. There are similar groups of cells in the anterior 

 somites, through which the oesophagus passes ; these lie on each 

 side of the subintestinal blood-vessel, but I could find no duct. 

 The oesophagus is a narrow, simple tube, the walls of which 

 are fairly thick and very vascular. In somite xiii the oeso- 

 phagus enlarges, and in somites xiv to xviii the diameter is 

 some three or four times greater than in front. This ''crop'' 

 has a whiter appearance, due to its thicker muscular walls, 

 than the rest of the oesophagus ; it is deeply constricted as it 

 passes through the septa, and the wall is greatly folded in- 

 ternally. I almost expected to find that this was a gizzard, 

 but the structure is quite the same as that of the oesophagus. 

 In the nineteenth somite the crop narrows and becomes the 

 intestine, the walls of which are fairly thin, so that the dark 

 food-material is seen through. 



Vejdovsky states that there is no typhlosole, but on slitting 

 open the intestine along one side, and examining its interior, 

 a moderate-sized typhlosole is seen on the dorsal wall. 

 Series of sections confirmed this observation, and showed that 

 the epithelium covering this in-pushed dorsal wall diff'ers 

 somewhat from the rest of the lining in that the cells are 

 here longer and more regular in size. The typhlosole then 

 is present, and in it a small typhlosolar vessel or irregular 

 blood space, into which vessels from the intestine wall enter, 

 and from which small vessels pass vertically into the dorsal 

 blood trunk, just as is the case with Lumbricus. How far 

 back the typhlosole extends I am unable to say. 



' Perrier, " Iiltudes sur I'organisatioa des Lomb. terrestrcs," 'Arch. 

 de Zool. Exper. et Gen./ ix, 1881. 



