Nicholls and Jackson. — -New Specie.'^ of Mrc/aloscolcx. 145 
close as to make the openinj^ almost ai)pear to bo a common pore 
(PI. XVIII, fig. 10). 
Megascolex affinis sp. nov. 
Plate XVIII, Pigs, o, 4, and 5. 
This worm comes from the South-West of Australia, but un- 
fortunately the locality label lias been lost ; only one specimen Avas 
obtained. It approaches very closely to Megascolex imparicystis, 
the chief point of difference being the reduction of the accessory 
glands to Avliat appear to be mere thickenings of the body wall in 
the median ventral region intersegnientally at 17/18 and 18/19. 
Dissection shows that a rudimentary third pair of sperm sacs is 
present on septum 12/Pl, 2 >’‘<^tj^‘cting into segment 13. This is an 
unusual condition, for, as a rule, wlieu three pairs of sperm sacs 
occur they lie in segments 10, 11 and 12. Other points of difference 
are: the length of the duct of the sjiermiducal gland, Avhich is 
greater than that of the same <luct in M. ioiparieystis as described 
by Michaelsen, being slightly longer than the glandular mass; the 
beginning of the mid-gut in segment 17 instead of in segment 18; 
and the occurrence of strongly developed muscle strands connecting 
the thickened septa in the anterior region. Michaelsen does not 
mention the occurrence of such strands in M. imparicystis. In the 
present species the strongly developed condition of these muscles 
and the cup-like shape of the thickened septa Avliich they connect 
are very reminiscent of the same structures in Megascolides australis. 
Specific Diagnosis. Length (in spirit): 140 mm.; breadth, 8 
mm. ; number of segments, 105. 
Colouring : Greyish broAvn dorsally, yellorvish-Avliite ventrally- 
There is no visible clitellum. 
There are five unpaired spermathecal pores lying mid-ventrally 
in furroAVS 4/5 to 8/9 (PI. XVIII, fig. 3). 
The male pores are in segment 18, close to the mid-vential line, 
and are not marked by the presence of pajjillae. 
There are no obvious accessory glands, but there is an extremely 
small transverse swelling in the mid-ventral region of furrows 17/18 
and 18/19. 
Dorsal pores are present. 
Anatomy. Septa 7/8 to 15/16 arc thickened, and are comiected 
by muscle strands. Of these, septa 7/8 and 15/16 are but slightly 
thickened, Avhile the intermediate septa 8/9 to 14/lo are very thick. 
