THE ANATOMY OF AMPHIPTYCHES URNA. 143 
Caryophyllgus, alone amongst Cestodes, so far as I am aware, possesses a definite 
receptaculum seminis, a structure characteristic of forms which are not self-fertilising 
amongst hermaphrodite animals. In the former the structure is more definitely 
developed than in the latter, and has an external opening distinct from that of the 
other organs. 
It is quite possible that this spermatheca serves to store up the spermatozoa 
of some other form, and not those produced in its own testes. 
(a) Male Organs.—Wagener has described as testis a structure lying at the 
anterior (according to him posterior) end of the reproductive organs, and which 
certainly contains ripe spermatozoa. This structure, however, is to be regarded as 
a receptaculum seminis, and as such will be described in connection with the female 
organs. 
The real Testes are a series of somewhat globular, sack-like structures, scattered 
about irregularly in the posterior part of the body (Pl. 11, Fig. 1, ¢e.). They are 
placed to the sides of the hinder part of the uterus, and extend backwards as far as 
the posterior sucker. In these testes, which in their scattered nature agree generally 
with those of other Cestodes and of Trematodes, the spermatozoa are to be found in 
different stages of development. Hach testicular mass is enclosed in a capsule of 
connective tissue, the walls of which are lined by mother cells. The outline of these 
cells cannot be clearly determined, and the structure has rather the nature of a 
protoplasmic syncytium containing numerous nuclei. Cells apparently separate off 
from the wall, and dropping into the cavity of the capsule, undergo division, and 
develope in much the same way as in many other worms (¢.g., Chotopoda and 
Turbellaria). Sperm-blastophores could not be clearly distinguished, but the 
spermatozoa remain grouped together as they do when one is present, and in all 
probability such a structure is developed from a portion of the spermatosphere. 
Fine ducts, very difficult to distinguish and probably only fully developed when 
the spermatozoa are actually in the act of transit to the exterior, pass from the testes 
into a common duct on each side, which again opens into a coiled tubular organ, 
which in part overlies the posterior end of the uterus. These are the structures of 
the exact nature of which Wagener was in doubt, and which, judging from his 
description, I believe he described as ‘“‘ Keimstock,” stating that their nature was 
doubtful. 
The coiled tube, which is filled with a curious coagulated material in hardened 
specimens of the worm, is to be regarded as a vesicula seminalis. From it one of the 
curiously coiled tubes noticed by Wagener, but the exact connection of which he was 
unable to determine, passes off towards the left side of the body; this tube is 
