THE ANATOMY. ALIMENTARY CANAL 



61 



Fig. 14. 



resemble, according to the same author, fat particles ; besides these round particles 

 which constitute what is called by Glapaekdb ' Kalkmilch,' there are in the first pair of 

 these glands rhomboedra, and larger concretions are figured but not specially described. 

 These latter show radial striations. The large concretions as well as the small 

 spherules are figured by Lankester. In Pontoscolex Peeeiee mentions only the fine 

 spherules. In Microdrilus I have found rhomboedral crystals and also in Eudrilus. 

 That these particles are formed of carbonate of lime seems to be proved by the fact 

 that they dissolve in acetic acid, giving off carbonic acid. 



Besides the glands already described there ar^ other diverticula of the oesophagus 

 which seem to be the equivalents of the calciferous glands, but are of different structure 

 from those described and from each other. The Enchytraeidae have been known since 

 the careful investigations of Vejdovsky (3) and Michaelsen (1-4) to possess glands 

 appended to the anterior pai-t of the alimentary tract which have been termed by 

 Michaelsen ' Chylustaschen,' and regarded as homologous with the similarly named 

 structures in the Eudrilidae ; these occur in two varieties : — 



In Buchholzia there is a single dorsal pouch from which arises the dorsal blood- 

 vessel ; this pouch communicates with the oeso- 

 phagus by a wide orifice ; its interior is 

 however not a simple lumen but is occupied 

 by a mass of tubules or by a single much 

 convoluted tubule, which has the appearance 

 of a nephridial tubule, inasmuch as it has an 

 intra-cellular lumen ; the interspaces between 

 the tubules is occupied by blood spaces ; from 

 these arises the dorsal vessel; this apparently 

 single pottch is really composed of two closely 

 applied pouches ; its lumen is not ciliated. 



In Fridericia leptodera there is a pair of 

 diverticula with ciliated lining epithelium, 

 and in Henlea ventriculosa two pairs of such 

 diverticula ; the degree of folding of the 

 lining epithelium varies somewhat. These structures are obviously related to the 

 diverticula of earthworms, but it is not so certain whether the remarkable glands 

 of Buchholzia are. 



The latter are to some extent paralleled in another genus, Gordiodrilus; in 

 the four or five species belonging to this genus there opens into the oesophagus 

 on the ventral side an ovoid pouch. This pouch is formed in the first place by 



BUCHHOLZIA. CALCIFEROUS GLAND. 



(After Michaelsen.) 



1. Peritoneal layer. 2, 3. Tubules of gland 4. 

 Dorsal vessel. 5. Lumen of intestine. 6. Ventral 

 vessel. 7. Peritoneum. 8, 9. Muscular and epi- 

 thelial layers of intestine, 

 intestine. 



Vascular sinus of 



