FowT species of Microcotyle. 237 



anterior end of tlie gToup of testiculai" lobules. There it doubtless 

 receives the vasa effereutia from tliese lobules, altliougii they,can 

 only occasioiially be traced in the sections. The lobules of the 

 testis of whicli there are about one hundred, are sharply outlined 

 thin walled sacs filled looselj^ with a mass of Spermatozoon forming" 

 tissue. 



The process of the formation of spermatozoa cau be seen beauti- 

 fully in these lobules, for all stag-es are found side by side. There 

 are irregulär masses of large cells lying- close against the wall of 

 the lobule and it is apparently from such larg'e Clements that, by 

 further subdivision, rosettes or balls of very much smaller cells are 

 formed; later stages show even these minute seg-ments subdivided 

 and long fllaments of protoplasm Streaming out from the central 

 mass. In other instances one sees pale bluish spheres in which a 

 few well formed spermatozoa are scattered about a formless central 

 dense mass as though from one of the rosettes nearly all the fully 

 formed spermatozoa had been cast off. Such free spermatozoa are 

 to be found also in sheaves. 



In the parenchyma just ventral to the ejaculatory apparatus 

 there is embedded a curious structure of chitinous appearance. Its 

 connections are very hard to make out but apparently it Stands in 

 some relation to the cirrus. It consists of four central rods arranged 

 almost in the form of a "W" the outer points of which are continued 

 in a curve to a point far behind in the parenchyma (Fig. C sp). Of 

 the function of such a formation it is hard to gather any idea 

 al though chitinous spines are by no means uncommon about the genital 

 openings in other forms. Here the spicules seera to be entirely 

 embedded in the parenchyma and quite away from the surface. 



The ovary lies in the middle of the body as a long tubulär 

 structure much folded and coiled upon itself (Fig. D). Starting 

 posteriorly at the right side it curves across to the left, turns for- 

 ward on itself, then across again to the right side and back nearly 

 to the point where it began. In this course the ova which it con- 

 tains become continuously larger and more mature. The oviduct is 

 a rather wide tube which runs backward to meet the common yolk 

 duct which results from the union of the two main lateral yolk 

 ducts which run anteriorly and brauch off to the lobules of the 

 vitellarium. The combined canal runs further back, giving off a 

 thick walled Channel which contains yolk cells and granules and then 

 turns dorsally to join at its beginning the bulbous end of the uterus. 



