1901.] FKOil BRITISH EAST AFRICA. 330 



Polytoreutus. The two glauds open on to the exterior by a median 

 bursa copulatrix of circular outline, which of course underlies the 

 uerve-cord and the end of the spermathecal >sae. 



A more careful examination of the spermiducal glands shovv.s 

 that they can, like those of Polytoreutus gregorianm for example, 

 be divided quite plainly into two regions. The "elbow," already 

 mentioned, mai'ks the boundary-line between these two regions. 

 The proximal part of the gland, I. e. that which is nearest to the 

 orifice into the bursa copulatrix, is perhaps one half of the length 

 of the rest. It is oval in form and gradually tapers to a slender 

 tube, which opens into the bursa copulatrix. At the very extremity 

 of the latter, just before its orifice into the bursa, opens the sperm- 

 duct, which is here as elsewhere co\ered with a thick layer of 

 muscular fibres which dilate the duct to twice the diameter it would 

 have were there no muscular coat, and, of course, thus accounts for 

 its prominence in dissections. The distal part of the spermiducal 

 gland has nob the lateral diverticula that occur in Poh/tor-eiitiis 

 ccendeus, according to Michaelsen's figures and descriptions ^ ; but 

 it presents some hint of this in a series of irregularly disposed 

 bulgings of the wall of the tube. The bursa copulatrix appears to 

 have a circular contour ; but when the upper part into which the 

 spermiducal glands open is pushed aside it is seen to commiuiicate 

 with the exterior by a curved peduncle, so that on a lateral view it 

 appears almost pear-shaped. 



The- sjjej'matheccd sac is like that of several species, including 

 P. Icilindinensis and P. finnl, in that it has but two diverticula. 

 The median part of the sac is very wide anteriorly and gradually 

 shrinks in diameter until — where it traverses the bursa copulatrix — 

 it is of quite small diameter ; from the anterior end two relatively 

 huge lateral sacs are given otF, one on each side. These reach back 

 to nearly the point of external opening of the sac. From the 

 underside of each of these, quite hidden until the diverticulum is 

 lifted up, arises the tube communicating with the egg-sac and the 

 oviduct, the arrangement of which parts is as in other species of 

 the genus, there being also a representative of what Michaelsen 

 has termed the " Samenkammerchen '' in Polytoreutus ca=ruleus, &c. 



This seminal chamber is a very extraordinary formation. In the 

 specimen which I examined there was but one instead of the four 

 figured in Polytoreutus cceruleus by Michaelsen. The single chamber 

 was choked by a mass of ripe spermatozoa (as I interpret the 

 structure in accord with Michaelsen), the tails of which depended 

 into the lumen of the oviduct, while their heads were apparently 

 fixed in the epithelium of the chamber ; this recalls the case of 

 the spermathecal diverticula of many Megascolicidse, where, as I 

 first showed ^ the spermatozoa are confined to tlie diverticula and 

 are there attached to certain glandular cells. 



• ^ " Beschreibung der von Herrn Dr. Franz Stuhlmann ini Miinclungscebiet 

 des Sambesi gesaramelten Terricolen," JB. Hanib. wiss. Anst. vii. pi. i fio- in 

 p. 24. '■ ' 



2 " On the Specific Characters, &c. of certain New Zealand Earthworms " 

 P,Z.S. 1885, p. 830. 



