1920.] J. Stephenson: Oligochaeta from India and E. Persia. 227 



viii and ix respectively. So too the prostatic apertures are in previous species pos- 

 teriorly on xvii and anteriorly on xix, or actually in the furrows 17/18 and 18/19 5 

 while here they maintain their original position at the middle of xvii and xix. 



Lastly, the testes and funnels are free in segments x and xi in the former species 

 but are contained in testis sacs in the present form. Here I am not clear as to which 

 is the more primitive condition. As a rule, of course, the free condition is to be 

 looked on as primitive, and that in which the testes and funnels are enclosed in sacs, 

 — separated-off portions of the coelom, — as secondary. But in the previous species 

 of the genus the testes and funnels are not free in the usual sense ; segments x and xi 

 are very narrow, and septa 9/10, 10/11, and 11/12 are fused together at their periphery 

 so as, at first, to give the impression of one enormously thickened septum. What 

 has happened is that these septa have become approximated, and the contained seg- 

 ments very much contracted ; whether originally, before the contraction took place, 

 they contained testis sacs cannot now be decided, — the sac-walls (if the sac originally, 

 as in the present form and often elsewhere, contained alimentary canal, hearts and 

 dorsal vessel) may have simply fused with the walls of the segment. 



I have previously (13) shown that Hoplochaetella is to be regarded as the ances- 

 tor of Erythraeodrilus. In some ways the present form may represent that ancestor 

 more closely than any of the previous species ; thus the condition as regards testis 

 sacs is the same in this form and in Erythraeodrilus, and similarly with regard to the 

 number and position of the seminal vesicles (three pairs in this form and in Erythrae- 

 odrilus, in segments ix, x, and xii ; two, in ix and xii, in the other species of Hoplo- 

 chaetella). The distinctive difference between Hoplochaetella and Erythraeodrilus is 

 the presence of two pairs of prostates in the first, of one pair only in the second ; in 

 this, the present form agrees with Hoplochaetella, along with which I propose to in- 

 clude it, widening the previously given definition of the genus (as regards the endings 

 of the vasa deferentia, the positions of the prostatic and spermathecal apertures, and 

 the free testes and funnels) for the purpose. 



Hoplochaetella spp. 



Daman Road, N. of Bombay (between Bombay and Surat). 7-vii-1917. B. Prashad. Five 

 specimens, none sexually mature. 



Bombay, Malabar Hill, l-vii-1917. B. Prashad. Numerous specimens, none mature. 



Bombay, Elephanta Island, high up on a hill. 30-vi-1917. B. Prashad. Numerous speci- 

 mens, none mature. 



In the specimens from Malabar Hill the spermathecae could be seen on dissection 

 to be just forming ; they appeared to end in the furrows 7/8 and 8/9 ; if so, the ap- 

 proximation of the two pairs has not gone so far as in the majority of the species, 

 where both pairs are on segment viii. 



The specimens from Daman Road presented one point of interest to me. The 

 type of the genus Hoplochaetella is Bourne's Perichaeta stuarti ; and in identifying my 

 former five species as belonging to this genus (13), one point which came up for dis- 

 cussion was that Bourne described certain diverticula of the intestine which I did 



