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 3. Aspidogaster conchicola. 



Preliminary Note. 

 By J. Stafford, Zool. Lab. Leipzig. 



eingeg. 3. Mai 1895. 



Having been occupied for some months with researches into the 

 structure and development of Aspidogaster conchicola, I desire to state 

 here, as briefly as the subject permits, a few of my results. Details 

 will appear in a future paper. 



Cross sections of the adult animal show a transverse muscular 

 septum separating the intestine, vitellaria, and end organs of the 

 sexual system above from the large vessels of the excretory system, 

 the lateral nerves and the hermaphrodite genital glands below. At 

 the posterior end of the intestine the septum thins out and its indivi- 

 dual fibres are lost in the parenchym, so that here the infra- and supra- 

 septal portions of the body pass directly into one another. Underlying 

 the infraseptal division and separated from it by a limiting membrane 

 is the ventral disk — a highly complex sucker-apparatus. Into the 

 structure of this as well as of the body parenchym and musculature 

 I do not purpose here to enter. I only mention the above stated facts 

 to indicate the relative positions of the chief organs of the body, since 

 Voeltzkow states that the »Expulsionsschlauch« and the lateral ner- 

 ves lie in the »Saugscheibe« and posteriorly pass out of it into the 

 body. They are in fact situated right and left from ovary and testis, 

 from which they are separated only by parenchym; above them 

 stretches the septum and below them the limiting membrane of the 

 ventral disk. Voeltzkow could not have meant to call the whole 

 infraseptal part a »Bauchscheibe«, for then the sexual organs would be 

 in the sucker. The part of the animal below where the septum joins 

 the body walls on the sides and front, however, adapts itself to the 

 conditions of contraction and expansion of the ventral sucker, being 

 sometimes much lengthened while sometimes it is much broader than 

 the upper part of the body. It acts so much as a unit, that one is 

 tempted to give it the particular name of foot in contradistinction to 

 the neck and supraseptal part. 



On each side, in the ventral sucker, is a longitudinal nerve with 

 a collateral plexus system , the whole in communication with the mar- 

 ginal sense organs by means of thick lateral branches. 



Both Voeltzkow — in his work of 1887 — and Zacharias in 

 a publication of the beginning of the present year state that they were 

 unable to find »Trichterorgane«. This I had already done before the 

 publication of the latter work. As near as I can judge, the three 



