Anatomical structure of Aspidogaster conchicola. 503 



motion they may change greatly in appearance and visibility due to 

 the contracted or expanded condition of the sucker. If the worm is 

 cleaving to the cover glass of a preparation, under slight compression, 

 the border alveoli of the sucker may creep outwards so as to leave 

 the whole foot flattened out and very thin. Then these glands, by 

 their contents and greater density than the surrounding parts come 

 best into view. Such a preparation may have part of the fluid sucked 

 out by blotting paper allowing the cover glass to sink till the worm 

 is compressed and fastened, and then by surrounding the cover slip 

 with a layer of wax it is fixed to the slide so as to permit use of 

 the oil immersion. In this way these glands may be found to lie in 

 the two middle rows of alveoli of the sucker and so appear to be 

 between the large excretory tubes when, under low powers, one can 

 not judge of perpendicular distance. They do not extend to the 

 anterior border of the sucker but only to about the level of the fifth 

 marginal sense organ. Voeltzkow's statement that they lie only 

 anterior to the ovary is not quite correct. It is true that they are 

 much more evident here and seem often to pass rather suddenly out 

 of view in the region of the genital glands. Posterior to this is a 

 much more unfavorable district to study on account of the impos- 

 sibility of getting the body pushed to one side; but it can still be 

 found that they are present although in a less developed degree — 

 smaller cells, more scattered groups — posterior to the testis. In 

 the living animal so prepared the cells are pressed over and into one 

 another so as to make it impossible to follow their outlines clearly 

 or to find unmistakable ducts. Often the glands run out a little 

 towards the margins of the sucker in somewhat pointed projections 

 corresponding to the positions of the sense organs. In several pre- 

 parations made as I have described, when the slide was so turned 

 under the microscope that the anterior end of the Aspidogaster was 

 directed away from me, I have found, on the right hand side, two 

 successive projections forming continuous strings running directly to 

 the fifth and sixth sense organs. That there are corresponding con- 

 nections with all the rest of the marginal organs, and that those I 

 saw are only by chance more evident than the rest, I can not at 

 present decide. These strings gave me the impression of bundles of 

 several tubes somewhat closely connected or wound together and con- 

 taining finely granular contents. 



In some of my preparations of sections these glands can not at 

 all be recognized, while in others when one has once become suspicions 



