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membrane with scattered nuclei. The muscle layer is well developed, 

 and consists of a single layer in which the component fibers extend 

 around the organ in a transverse direction, thus forming a circular 

 layer. It is about equally developed in all parts of the ampulla, and 

 in the region of the junction with the digestive tract this layer passes 

 over into the muscle layers of the latter. It is, however, very dif- 

 ficult to determine the exact structure of this transitional region, and 

 the writer has not been able to demonstrate with absolute certainty 

 to which of the muscle layers of the digestive tract it becomes allied. 

 It seems to pass into the circular layer, as one would expect, and 

 further evidence in support of this conclusion will be given later, 

 when it will be shown that this muscle layer connects with the cir- 

 cular layer of the body wall. The epithelial layer of the ampulla con- 

 stitutes the greater part of the mass of the organ. It is composed of 

 tall, columnar cells, set closely together and distinctly nucleated at their 

 bases. In all parts of the organ this layer is thick, and especially so 

 in the enlarged part, where it is particularly thick and heavy, and 

 the length of its component cells is many times greater than their 

 diameters. This is a one-celled layer. In longitudinal sections of the 

 ampulla this fact is clear enough in the ental region, where the ampulla 

 connects with the digestive tract, but in the swollen region, where the 

 layer has its maximum thickness, it appears at first sight to be com- 

 posed of more than one layer of cells since more than one row of 

 nuclei appear in the same section. These cells are, however, closely 

 set, and sections of the usual thickness include parts of from two to 

 three superimposed layers, thus giving the appearance referred to 

 above. 



The part of the spermatheca extending from the ampulla to the 

 external opening is really the duct but is not sharply set off from the 

 ampulla. It has a rather peculiar structure. The epithelial layer 

 which lines the ampulla is interrupted completely, and the wall of the 

 duct is composed of two kinds of elements only, the muscle layer, and 

 the gland cells of the large gland which surrounds that region. This 

 gland is composed exclusively of very long cells which extend from 

 the periphery to the lumen of the duct. The nuclei are situated in the 

 peripheral ends. In a longitudinal section of the spermatheca these 

 cells have the appearance of having their inner ends cut off by a 

 band of muscle tissue which separates this glandular region into two 

 parts, one part lying between the lumen and the muscle band and the 

 other lying beyond the latter. This appearance is further emphasized 

 by the fact that the tissue outside of the muscle band stains readily, 

 while that between the muscle band and the lumen does not take the 



