AND ZOOGEOGRAPHY OF INDIAN OLIGOCU^TA. 123 



(XJpp = uppermost position, not far from mid-dorsal line; mid.= 

 middle position, at level of lateral setae; low.=lowest position, 

 at level of ventral seise.) 



Eight. 



Left. 



mid/ 



upp. 



\ov,\. • 



mid. 



mid. 



upp: 



Iqw. 



upp. 



mid. 



upp. 



mid. 



mid. 



low.- 



upp. 



mid. 



mid. 



mid. 



■ mid. 



mid. 



upp, 



mid. 



upp. 



(2) The Testis Sacs (Sperin-sacs). 



Beddard describes the sperm-sacs of U. harwelli (6). Pie 

 makes the interesting suagestion contained m _ the iollowing 

 extract (postscript to 6) :— " The remarkable partial obliteration 

 of a segment (the xiiith) wliich Michaelsen has recently described 

 iii Nemertodrihis griseus, suggests that something of the same 

 kind may have occurred in the Moniligastrid^e, the supposed, 

 sperm-sacs may be all that is left of the ccelom belonging to the 

 segment which contains the testes. This is, of course, no more 

 than a suggestion ; but the varying position of the essential 

 organs in the Oligochseta requires, as I point out m a forthcoming 

 number of the ' Quarterly Journal of Microscopical Science, some 

 possibility of the intercalation or excalation of segments at_ tne 

 head end." The sacs are also described by Benham m B. tndi- 

 ctos (10) where the cavity is traversed by muscular fibres passing 

 in different directions ; and by .Bourne in D. grandis (11). 

 ' As in all species of the genus Drcmida, the testis sacs, 

 containing the testes, male funnels, and ripening spermatozoa, 

 are in the present species a single pair, suspended by septum J 10. 

 In some species of the genus they, project about equally into 

 segms. ix and x, in some they project forwards into ix more than 

 backwards into x ; often there are differences on the two sides- 

 individual differences, not specific. In the pi;esent species the 

 sacs proiect backwards more than forwards. The appearance is 

 somewhat, as if the septum had split, the sacs being cavities 



within "it (fig. 2). • „ , i xi i 



Both anterior and posterior walls of the sac have the usual 

 peritoneal (p.), connective^tissue, and muscular («.. components 

 The inner lining of the sac is in places a cubical or flattened 

 epithelium {ep.) ; over the greater part of the wall, however, the 

 lining is not distinguishable from the mass of cells which fils the 

 ^^^■^^ Tj^-g j^,^33 stains of a pinkish colour with eosm {g.), cell 



