Anatomical structure of Aspidogaster conchicola. 533 



appearance is heightened by the greater amount of protoplasm in 

 these cells over those of the parenchyma. 3) In a section through 

 an animal with eggs in its uterus and where sexual reproduction has 

 been continued for some time, this body measured 0,08 X 0,113 mm. 

 Its lumen, now more irregular in shape, and not a single chamber, 

 but presenting a more or less spongy cavernous structure, measured 

 0,02 X OjOßi but of course this varied in successive sections. Contents, 

 broken up, indistinguishable masses, and numerous black globules of 

 various sizes from small dots to the size of a nucleus. The walls 

 are now more dense than before and exhibit no traceable cell structure. 

 The mass, however, tends to show thick and thin places, the latter 

 running in lines but not in a definite, regular direction. In some 

 preparations the sections break into layers in the direction of the 

 edge of the microtome knife, similarly to what I have seen in structures 

 laden with albumen (e. g. the intestine of an embryo leech). Nuclei 

 are more numerous than in the last named stage, and the whole 

 structure presents a marked contrast to the surrounding parenchyma 

 cells in the deep staining of its centents and numerous nuclei, while 

 the parenchyma cells have become empty looking and, in many places, 

 without nuclei. In another, differently preserved preparation of frontal 

 sections, the whole organ cut horizontally through the entrance of the 

 canal, 0,120 by 0,133 mm, while the cavity at its broadest place is 

 0,043 mm. The inner membrane (epithelium) from the canal was 

 visible, with nuclei, while the nuclei of the thickened parts were of 

 two kinds: — one resembling the epithelial nuclei, measuring 4 to 

 5,3 j«, nucleolus 1,3 /^i, or no nucleolus, and then the nucleus not pale 

 but containing dots; and a second, larger kind of nuclei, of 8 to 9,3 /< 

 diameter, with nucleolus 2,6 fi. Many of these nuclei were longer 

 than broad, and one I measured, was 6,6 X 10,6 /<. The structure 

 of the walls was indistinct but somewhat fibrous in appearance. In 

 the lumen were a large yolk cell, 17,3 /.i^ in rather normal appearance 

 and some yolk globules of muddy, disintegrated look. 



A glance at Pagenstecher's fig. 1, tab. 4, can not fail to show 

 that this posterior end of the Laurer's canal, with its brown contents, 

 was known to him. Voeltzkow was the first to trace its connection 

 with the oviduct. It was regarded by him as a receptaculum 

 vi te Hi, and the canal connecting it with the genital organs its duct. 

 Such an organ would indeed be quite new. In the period of sexual 

 efficacy, when the vitelline glands are large and distended with their 

 yolk cells, and all the ducts from them filled, as well as the expanded 



