7ieio Genus of Oligoclimta. 87 



similarly placed vessels which occur in the Eudrilidixi. The 

 calciferous pouch is thus very vascular, fully as much so as 

 the tract of oesophagus from which it arises. This, however, 

 is not all that I have to say about the minute structure of 

 this organ. The lumen of the pouch does not end blindly a 

 little way in front of the CKcal extremity of the pouch ; it is 

 prolonged up to nearly the end, becoming gradually narrower. 

 Just before the extremity of the gland it becomes slightly 

 wider, and communicates loith a network of fine tubes spread 

 over the greater part of the j')eripherij of the gland. These 

 tubes have an intra- cellular lumen. They lie just below 

 the blood-vessel which collects and carries away the blood 

 from the pouch, and are of such small calibre as to be very 

 inconspicuous. They are shown in fig. 2 in a longitudinal 

 and vertical section of the pouch. Fig. 3 represents a 

 portion of the network seen in tangential section through a 

 portion of the perij^hery of the pouch. Both these figures 

 show a structural feature of great interest if it proves to be as 

 in those drawings. Fig. 3 is a drawing which I have 

 endeavoured to make as accurate as possible of a portion of 

 the network referred to. Fig. 8 is a compound figure of 

 which the details have been filled in from more than one 

 section. In fig. 3 the netivorlc is shown to be continuous 

 with a tube (a), which is jmrt of the nephridium of the ninth 

 segment. I confess at once that only one specimen out of six 

 series of sections of this and the following species shows the 

 connexion between the nephridium and the intra-cellular 

 network of the calciferous pouch. But I can see no reason 

 for doubting the accuracy of my drawing ; moreover in the 

 other sections there were no appearances in any way opposed 

 to this interpretation. If confirmed, this fact is evidently of 

 some importance. I ought to mention, however, that the 

 nephridia of the ninth segment, which I believe to be con- 

 nected with the calciferous pouch, also open on to the exterior 

 in the usual way. Before treating further of the connexion 

 of the nephridia with the pouch, I may compare the pouch 

 with similar structures in otiier Oligochteta. 



Calciferous glands, cesophageal glands, or glands of Morren, 

 as they have been variously termed, exist in nearly ail earth- 

 worms. The only family from which these structures are 

 consistently absent is tliat of the Pericluutidte. Among the 

 lower Oligochajta the Enchytreida3 alone possess similar 

 glands. Dr. Michaelsen, of Hamburg, distinguishes two kinds 

 of these glands in earthworms, which he calls respectively 

 " Kalkdriisen " and " Chylustaschen." To the latter belong 

 the unpaired median pouches of the Eudrilidaj, which were 



