504 JOSEPH STAFFORD, 



of their whereabouts they can be found. Sublimate -haematoxy lin, 

 and picro-acetic acid with picro-carmine , have given preparations 

 where they are quite plain. They lie directly under the limiting 

 membrane of the sucker as large, distended, granular cells (Fig. 2, 

 7, 5 SG), each with a nucleus. They occupy the position in the two 

 central rows of alveoli that is otherwise taken up by the crowds of 

 sub-cuticular-like cells. Where the glands do not occupy the whole 

 space but lie in groups and form projections the above named cells 

 lie between the projections or groups. These glands do not fall into 

 the same category as those described above (skin-glands etc.). 



Zacharias takes it that the glands in question are the same that 

 he describes as anastomosing unicellular glands close under the skin 

 and which as I have already shown are nothing else than the ordinary 

 skin glands. It is evident that Zacharias found nothing agreeing 

 with VOELTZKOw's description. 



That these are all true glands and not at all to be designated 

 with the epithet "hypothetische Drüsenorgane" I am certain but I am 

 far from being certain of their function. I have before mentioned 

 that their secretion may be seen in the form of drops extruded through 

 the cuticula and hanging at the mouths of the glands. So far as I 

 can see it is possible for this to be made use of in one of three 

 ways : 1) stimulation of the surface of the host upon which the para- 

 site is found to the exudation of juices that can serve as nourishment, 

 2) as an assistance to the suckers in performing their function of 

 cleaving, and 3) as protection for the surface of the animal against 

 the injurious action of water or animal fluids. In judging of the 

 probability of any one of these possibilities we must take into account 

 the localization of the glands. As they do not occur at least to any 

 great number along the back and sides down to the septum and in 

 the posterior end the third proposition would seem to be shut out. 

 That the drops of secretion are soon disintegrated by the action of 

 water might be further proof although that does not prove that the 

 secretion would suffer a like decomposition under the action of blood 

 etc. Moreover it is the evident purpose of the cuticle to perform this 

 work. As to the second proposition we should expect the glands to 

 open onto the cleaving surfaces of the suckers. While the circum- 

 pharyngeal glands open in a favorable position, and some of the head- 

 glands also — round the border of the mouth funnel — the majority 

 of these are distributed on the surface of the neck where they can 

 have no such action. The same may be said of the foot glands which 



