1894.] NEW GENERA Or EAKTHWOEMS. 387 



terminal chamber of the efEerent apparatus in the genus Geoscolex, 

 and it is of course also comparable, as I have already mentioned, to 

 the bursa copulatrix of the Eudrilidse. The walls are thick and 

 muscular and of a spongy texture. At the posterior inner 

 boundary of each sac opens the spermidueal gland. The gland has 

 the tubular character of that of the last species, but it is decidedly 

 more slender ; it is, as usual, divisible into two parts — the non- 

 glandular duct, and the glandular portion. The former is of a 

 fair length and slender. It widens out at its actual oritice into 

 the terminal sac. The glandidar part of the tube is long and 

 coiled and slender ; it is attached to the posterior border of the 

 bursa by a mesentery, which supports it and gives to it somewhat 

 the appearance of a minute vertebrate intestinal tract. The 

 sperm-ducts cross the sac towards the outer border; they are 

 enclosed in a muscular sheath, as is the case with the sperm-ducts 

 of Microdrilus and Pygmceodrilus. The thickness of tliis muscular 

 coat makes the sperm-ducts hardly, if at all, thinner than the 

 duct of the spermidueal gland. The sperm-ducts pass beneath 

 the terminal sac, so that it is just hidden on a superficial view and 

 opens into it at the posterior outer border, at the opposite 

 " corner," as it were, to that occupied by the orifice of the spermi- 

 dueal gland. There is, as in the last species, no trace whatever of 

 penial setae. 



There are but a single pair of spermathecse, which have moved 

 a segment further in front and lie in the viith instead of the viiith 

 segment. They have a remarkable arrangement which I have not 

 seen paralleled elsewhere. The two spermathecaB are very close 

 together ; in fact they are in actual contact above, but they are 

 separated below by the nerve-cord which runs between them. 

 The area in which the two pouches lie is walled off from the 

 surrounding space by a perfectly circular fold of muscle, which 

 arises posteriorly from the septum, but anteriorly from the ventral 

 parietes. This is really produced by a perforation of the septum 

 to let the spermathecae pass through it. Each spermatheca passes 

 through a foramen, so that it lies in segment A'ii. to a great extent, 

 but opens on to the exterior between segments viii./ix. The 

 spermatheca itself is the shape of a sock with a very short 

 foot ; the toe is directed backwards. The spermatheca is thick- 

 walled but very soft ; there is nothing apparent in the shape of a 

 diverticulum. 



The following is a table of the differences between tlie species : — 



Millsonia ruhens. Millsonia nigra. 



Male pores Paired. Unpaired. 



Spermathecal pores .. VII./VIIT. VIII./IX. 



Stout septa IX./XVII. IV./XIV. 



Sperm-sacs in XI., XIII. in XI., XII., XIII. 



Bursa copulatrix .... Absent. Present. 



