502 JOSEPH STAFFORD, 



of the sucker joins the iuteguraent. They do not penetrate the sucker 

 itself but pass through the cuticle of the sides and front of the foot, 

 just above the margin of the ventral disk. I have sections, however, 

 showing considerable lengths of glands intact and reaching the surface 

 half way between sucker and septum. These glands possess a nucleus 

 and agree in every way as to relations, apparent structure, character 

 of secretion etc. with those in the mouth sucker, neck and round the 

 pharynx. 



VoELTZKOW finds these "überall in der ganzen Haut, besonders 

 in der Nähe des Mundnapfes , in der Saugscheibe und dem Septum 

 entlang". That they are all to be classed together (head-, circum- 

 pharyngeal- and foot-glands) as skin glands I have already indicated. 

 That, generally, they are not everywhere uniformly distributed I have 

 also mentioned. That Voeltzkow took them to be present in the 

 sucker is not to be wondered at when we contemplate that he did 

 not direct special attention to the structure and relations of this organ. 

 And that they are situated along the septum seems , in compressed 

 animals, and until one has given the closest attention, to be the real 

 state of atfairs. Very often one gets the appearance as if there were 

 a couple of rows of these glands, in pairs, at regular intervals, along 

 the side of the body, about midway between the opi)osite margins of 

 the compressed animal, and continuing back from the cervico-pedal 

 pit. This is, however, only on account of the glands along the under 

 and upper borders of the sucker (Fig. 13 6r), under strong compression, 

 appearing iu the same field of view. 



Slime glands. Voeltzkow describes a third kind of glands: 

 "In der Bauchscheibe liegen ausserdem noch drüsenartige, breite, 

 flachgedrückte Gebilde etc." For a good while these structures escaped 

 me. I could neither find them in sections nor in the living animal. 

 Finally, however, paying special attention to this one point I dis- 

 covered the cause of their non-appearance, which will be made clear 

 from what follows. 



Looking down onto the foot when the body and neck are drawn 

 back, with not too high a power, can often be seen, seemingly between 

 the large excretory vessels, the darker, more compact, indefinitely 

 shaped structures in question. When the worm is suspended on the 

 surface of the fluid in a watch glass , and of course with its sucker 

 turned upwards, these glands can probably be seen to more advantage. 

 In some animals even under the best conditions they do not stand 

 out distinct from the other tissues, and in an animal capable of free 



