246 Janet W. Raff : 



that it is provided with only a single gizzard, which nevertheless 

 occupies two segments. He thinks it quite possible that in 

 this case there is really a pair of gizzards which have become 

 fused to form a single one. I have found it occupying only one 

 segment, the exact number of which is often difficult to deter- 

 mine, owing to the septa at this anterior region being very thin 

 and lying close to the canal, and to each other. 



(6) The oesophagus is the portion between the gizzard and the 

 intestine. It varies very much in form from the simple thin- 

 walled tube, whicli may be constricted at each septum, giving 

 the canal a pouched appearance, to the forms where the cal- 

 ciferous glands are present, forming in some cases large bean- 

 shaped diverticula. We must distinguish between those portions 

 of the oesophagus which are pouched, because of the constric- 

 tions at the septa, and those portions which are actually swollen 

 out in the segments. The former I refer to in the description 

 as " simple," the latter as " vascular swellings." They are easily 

 distinguished macroscopically by their walls, the vascular swell- 

 ings having a rough-looking surface owing to their inner lining 

 being folded, and, generally speaking, being richly supplied 

 with blood. The thin-walled, simple portions are generally in 

 the anterior and posterior regions of the oesophagus, while the 

 middle portion is modified in various ways. 



Calciferous Glands. — The term '" calciferous glands " seems to 

 have been used in rather a loose sense, and often, where the 

 alimentary canal of a certain w^orm is described as having 

 calciferous glands, I have only been able to find vascular swell- 

 ings. I have therefore restricted the term to those swellings in 

 the oesoj)hagus ivhich are not of the ordinary median kind, i.e., 

 winch are not simple vascular swellings. They may he saccula- 

 tions of a vascular swelling [Fig. 2], or diverticula of the 

 Desophagus [Fig. 3]. It is not necessary that they should be 

 separated from the median portion of the canal by a duct. 

 Thus in /''. niiicus they are in the form of small pouches, vary- 

 ing in number in the different segments, and not separated from 

 the median canal. It is just as if we had a large vascular 

 swelling indented at different places, and so giving it a sacculated 

 appearance. [Fig. 2.] So far as I have examined I find that 

 where tliey are in the least separated from the canal by a con- 

 striction or a duct, they are paired. 



