Anatomical structure of Aspidogaster conchicola. 521 



parts show one or more imperfect septa i. e. where the longitudinal 

 furrows are flattening out at the ends for it is evident that the in- 

 folding will be deepest at the place of greatest expansion. Anteriorly 

 all the septa fail to reach the sides of the papilla and flatten out 

 into the yet somewhat widened circular ductus which gradually nar- 

 row as it continues forwards into the middle portion of smallest diameter. 

 The septa fall short of the p a p i 1 1 a some distance posterior from its 

 anterior tip but continue as ridges along the inside of the outer 

 ductus for some distance anterior to the point of the papilla. In 

 the diagram I have indicated on the left side (by shading) one of 

 the septa while the right side falls along one of the canals. In Fig. 18 

 are ten perfect septa and one imperfect while the intervening canals 

 are ten in number one of which, however, on account of the imperfect 

 septum is double. This section is near the broadest part of the 

 bulbus while Fig. 17 represents a section of the bulbus through the 

 anterior end of the papilla where the septa, nine in number, are 

 present only as ridges in the inside of the outer ductus. A few 

 sections ahead of this the papilla is wanting, the ridges have faded 

 into a circular muscular tube of small size and the large space be- 

 tween this and the penis sack is occupied by parenchyma. The above 

 mentioned canals are really portions of the cavity of the ductus 

 ejaculatorius extending backwards as blind sacks along the outer sides 

 of the papilla (conus bulbi). They are lined with the continuation of 

 the inner coating of the ductus proper, which on their outer walls 

 exhibits nuclei, but along their sides are peculiar epithelium-like 

 bladders (Fig. 9, 17, 18 B) with distinct boundaries whose contents 

 show the presence of numerous granules but no nuclei. The signi- 

 ficance of these bladders is to me not altogether clear but I am 

 convinced that they stand in relation to the prostate ducts which 

 pass through the penis sack in rows corresponding to the septa, 

 penetrate the parenchyma and can be followed into the septa to the 

 bases of the bladder cells which are apparently their continuations. 

 In a preparation doubly stained in haematoxylin and alum-cochineal 

 the parts are beautifully ditferentiated : nuclei, cell boundaries of 

 prostate glands and of parenchyma, outer muscles of penis sack, 

 sperm having diâ"erent tinges of purple while other parts are stained 

 red. In these sections the same little bright red granules that are 

 found in the contents of the prostate glands are continued along their 

 bundles of fine ducts and are present in the bladder-cells. My first 

 impression was that these are drops of secretion fluid at the mouths 



