110 MISS G. SWEET ON THE SPERMIDUCAL 
somewhat flat finger-like bodies attached to the anterior septum 
in segments 10 and 11. They are enclosed in a very delicate 
membrane connected with the peritoneal lining of the general 
body-cavity. The sperm mother-cells, which originate by multi- 
plication of the cells of this peritoneal lining, pass out into 
(2) the seminal vesicles or sperm-sacs. These are generally 
found in pairs in segments 9 to 12, where they arise as out- 
growths of the septa, enclosing a small portion of the body-cavity. 
Here the sperm mother-cells develop so as to form by division 
the spermatozoa. These pass to the exterior by means of (3) two 
pairs of vasa deferentia. The latter open by means of two pairs 
of much-folded and ciliated funnel-shaped structures, from the 
segments in which the testes lie, and lead back through the 
following segments to open externally by a single pair of 
openings on segment 18, in the typical Australian Oligocheta. 
Associated with the external openings of these vasa deferentia 
are a pair of glands, the so-called ‘‘atria”’ or “ prostates.” The 
name “spermiducal glands,’ proposed for these glands by 
Beddard, is here retained as being the most appropriate. In 
addition, there are often present near the male pore other glands 
internally, or one or more “ penial setz.” 
These organs are in general constant throughout the group in 
many respects, but in detail they often vary widely in different 
species, both in structure and to a certain extent in position. 
A. Macroscopic CHARACTERS OF THE SPECIES. 
I. MEGASCOLIDES. 
1. M. wwrermentvs * (Spencer). 
Only one pair of testes and of rosettes is present in this species. 
Sperm-sacs are found in segments 12 and 14. 
The spermiducal glands (sp.g., Pl. 14. fig. 3) are tubular in form 
and slightly coiled: they lie transversely to the body in segment 
18, their ducts (sp.d.) opening on its external surface near the 
mid-ventral line. The duct of the spermiducal gland is almost 
straight and very muscular. ‘ The vas deferens on each side (v.d.) 
enters the gland-duct just where the latter leaves the gland. 
Occupying the space internally, between and covering the two 
spermiducal ducts, and below the nerve-cord, is a white mass of 
* Proc. Royal Society of Victoria, 1892, p. 182: Cryptodrilus intermedius 
(Spencer). Beddard, ‘ Oligocheeta,’ p. 492. 
