A NEW SPECIES OF MONILIGASTER FROM INDIA. 373 



Telmatodrilus, Eisen/ one of the Tubificidse^ presents 

 an intermediate condition between the arrangement met with 

 in Tubifex and that in Moniligaster ; for in this worm, 

 instead of the single group of gland-cells communicating with 

 the atrium, as in Tubifex and other of its allies, there are 

 eight or ten such isolated groups (fig. 16, b) arranged around 

 the upper part of the atrium, that is the '^ glandular part of 

 the atrium,'^ as I have called it in my description of Hete- 

 rocheeta.^ 



If now the atrium were to shrink, so to speak, these isolated 

 groups of gland-cells would be approximated, and there would 

 result a continuous coating of gland-cells, communicating 

 here and there through the muscular coat with the cavity of 

 the atrium, as we find in Moniligaster and Rhynchelmis. 



In other earthworms, such as Acanthodrilus, Peri- 

 chaeta, &c., the structure of the prostate has been dealt with 

 by Beddard (4); the chief difference from Moniligaster 

 being, as I believe, due to the restriction of the muscular coat 

 to the neck of the gland, and the consequently greater com- 

 pression of gland-cells against one another (fig. 16, e). 



In the " intermediate condition " (fig. 16, d) I have 

 imagined the muscular coat becoming more definitely confined 

 to the " duct,'^ though some of the glands still perforate it ; 

 whilst others are in a condition similar to that in Deino- 

 drilus, &c. 



The spermatheca presents certain interesting features. 

 The nearly spherical or slightly pyriform sac, lying above the 

 oesophagus in Somite viii, is provided with a very long deli- 

 cate, shining duct,^ several times coiled, which passes down- 

 wards to reach the body-wall in the anterior of the somite 



1 'Report of Commissioner of Fish and Fisheries for 1883,' p. 880, pi. 

 i,fig.l. 



* "Note on Aquatic Oligochseta," 'Quart. Journ. Micr. Sci.,' xxxiii. 



3 In M. japonicus Michaelsen mentions that he found only one 

 " Samentasche " on the left side attached to the body-wall between Somites 

 ix/x. If this is a spermatheca, it differs from the remaining species in being 

 without the very characteristic long duct, as well as in its position. 



