548 FRANK E. BEDDARD. 



has already shown in his brief account (6) of an evidently very 

 interesting form, Glyphidrilus Weber i^ that the position of 

 the clitellum hitherto found only among the Lumbricidae is 

 also to be found in a worm clearly referable to Perrier's 

 Intraclitellians. The varying position of the gizzard is less 

 remarkable now that there is some probability of its epithe- 

 lium being always derived from the hypoblast; if the older 

 view that the gizzard belonged to the stomodseal invagination 

 had been confirmed by more recent researches^ it would have 

 been necessary to regard the calciferous pouches as being 

 epiblastic when in front of the gizzard and hypoblastic when 

 lying behind it. The relations of the same diverticula show that 

 ■when the gizzard is followed immediately by the " large in- 

 testine '^ it does not mean that there has been a suppression of 

 the small intestine immediately following the gizzard. The 

 absence of any relation between the position of the gizzard (or 

 gizzards) and the position of other organs seems to show clearly 

 that this modification of the walls of the anterior section of 

 the gut may take place anywhere. There is no need to assume 

 that the gizzard of one earthworm is the exact homologue of 

 that of another. 



The pharynx occupies the first five segments. 



The cesophagus is of great length, and divided into two 

 distinct sections, neither of which, as already mentioned, is 

 furnished with glandular diverticula. The first section of the 

 tube is of narrower calibre, and extends as far as the end of 

 Segment 19. After this the tube becomes suddenly dilated and 

 forms a kind of crop, which immediately precedes the gizzards. 

 The '^ crop " occupies Segments 20 — 22 inclusive. 



As to histological structure, the oesophagus does not differ 

 from that of other earthworms ; its walls are exceedingly 

 vascular, and the epithelium is in many parts rather thin. 

 Even in the 12th segment there are a few chloragogen cells 

 upon the oesophagus. These become largely developed in Seg- 

 ment 15, where the oesophagus is as closely enveloped by them 

 as is the intestine ; the transition, however, appears to be 

 gradual. The latter part of the oesophagus from about Segment 



