THE GIANT EARTH-WORM OF GIPPSLAND. 31 
chromatin. The larger ones are in the rays where they all appear to be nearly of one 
size, and have very clear chromatin spots irregularly arranged around the periphery 
close to the nuclear membrane. 
No further development seems to be undergone in the testes, which can be found 
apparently at any time of the year. Worms secured in June, September and March 
contained them. They have at all times the same external appearance and the same 
microscopic structure, even in different worms in which the development (so far as 
size and extent is concerned) of the seminal reservoirs varies considerably. The 
evidence that these structures are really testes is both positive and negative. (qa) 
Positive (1) inasmuch as they contain structures indentical with the earliest stages in 
the development of spermatozoa, not only as found in other worms, but also as present 
in the seminal reservoirs of Megascolides. (2) Their position with regard to the 
segments of the body and relationship to the septa. (b) Negative—inasmuch as they 
differ uniformly in structure from the other reproductive organs of which it might be 
possible to regard them as early stages in development, viz., vesicule seminales and 
ovaries. 
In the vesiculz seminales, spermatozoa are, on the other hand, seen in every 
stage of development. The whole structure, besides occurring in scattered divisions 
in four distinct segments separated from each other by thick muscular septa, 1 
divided up into a great series of capsular chambers, in which very different stages of 
development are met with at the same time. 
How the testicular cells get into the seminal reservoirs cannot be stated, and it is 
difficult to imagine how from the testes in the tenth and eleventh segments the 
germ can pass backwards into the fourteenth segment, as the basal opening allowing 
of the passage of the ventral nerve-cord is very small indeed, and the septa very 
thick. It is to be remembered, however, that the testes lie on the ventral side, and 
so close to the openings through which, in alternate expansion and contraction, 
currents of the ccelomic fluid doubtless flow. 
In Lumbricus, the testis is enclosed during growth of the seminal reservoirs, and 
in Microcheta the testis is enclosed in a special ccecum of the reservoir, but, as stated 
above, the testis of Megascolides is never enclosed, and can be easily found at all times 
of the year. ; 
Each capsule of the reservoir is encased by connective tissue, and within the 
walls ramify numerous blood-vessels. The same seminal capsule, as a general rule, 
contains sperm in very different stages of development. The different stages are 
represented diagramatically in Fig. 15, which is supposed to be a single capsule cut 
in section, and containing within itself the different stages, not necessarily seen in the 
one capsule, but to be found at the same time in the same animal. 
The youngest stage is probably the small mass of cells (3) still jomed together, but 
with their outlines distinguishable and their nuclei resembling exactly the largest ones 
