1920.] J. Stephenson: Oligochaeta from India and E. Persia. 195 



Fam. NAIDIDAE. 



Genus Chaetogas ter. 



Chaetogaster bengalensis, Annand. 



Five miles S.E. of Nasratabad, Seistan, E. Persia. Small pool in the desert ; water fresh but 

 turbid, bottom muddy with a fairly rich growth of Potamogeton and reeds, mostly in a dying 

 condition. The specimens were on Limnaea gedrosiana var. rectilabrum, Annand. and Prashad, 

 26-XÜ-1918. N. Annandale and S. W. Kemp. 



Peshawar, N.-W.F. P. ; on Limnaea acuminata. 12-1-1919. N. Annandale. Several specimens. 



Kalpani stream, near Nowshera, N.-W.F. P. ; on Limnaea acuminata. 13-i-1919. N. Annan- 

 dale. Four specimens. 



Madhopur. Gurdaspur District, Punjab ; on Limnaea acuminata. 27-i-1919. N. Annandale. 

 Forty-nine specimens taken out of the mantle cavity of a single individual of Limnaea. 



Satara Fort, W. Ghats ; ca. 3,300 ft. 4-iii-1918. N. Annandale. On Limnaea chlamys, 

 Benson. 



The specimens from the Western Ghats and from Seistan were examined in some 

 detail. 



There is sometimes, in preserved specimens, a constriction between the pharyn- 

 geal region and the rest of the body. The length of the setae of segment ii is com- 

 monly 120^, of the rest 6o/x. In all the batches, 15 and 16 setae were quite com- 

 monly found in a single bundle. 



The appearance of the " crop " is rather characteristic, owing to its complete 

 investment of chloragogen cells. These have the arrangement of paving stones, lying- 

 side by side, and well demarcated from each other by linear intervals. The entrance 

 to the crop is marked, as in the specimens from the Inlé Lake (14), by a ring of tall 

 cells which project into the lumen. 



The lateral commissural vessels in the oesophageal region are never swollen or 

 heart-like. The dorsal vessel, on the other hand, is often dilated just behind the 

 origin of these commissures. 



The species appears to have a wide distribution, and to be the prevailing com- 

 mensal of Limnaea. It thus takes the place in India of C. limnaei, which is found 

 in a similar association in Europe ; Michaelsen has however found C. limnaei on a 

 specimen of Limnaea from the Kumaon District (Central Himalayas) (3). Last year I 

 identified several specimens from a sponge (Ephydatia fiuviatilis) from the Inlé Lake as 

 doubtfully belonging to C. limnaei (1 4) ; through the kindness of Dr. Annandale I have 

 recently had the advantage of comparing my examples of this form with a specimen 

 of C. limnaei sent to the Indian Museum by Dr. J. H. Ashworth of Edinburgh ; 

 but I am still unable to say definitely that the Inlé worms either are or are not 

 C. limnaei. The identification of these small worms from preserved material only 

 is, as I have previously explained (12), often both difficult and extremely hazardous. 



Chaetogaster spongillae, Annand. 



Khandala. W. Ghats ; from sponge [Spongilla crateriformis) in artificial tanks made by dam- 

 ming stream; bottom, — mud over rocks; some stones; weeds fairly abundant. 6-iii-1918 

 N. Annandale. 



