IL— DESCRIPTIVE PART. 

 FAM. NAIDIDiE. 



GEN. CH^.TOGASTER. 

 Ch^togaster IvImn^i, K. Baer. 

 Hab,— Western Himalayas, Naini Tal in the Kumaon district, 6,400'; 

 Dr. N. ANN AND ALE legs., 28-ix— 3-X-06. 



GEN. NAIS. 



, Nais obtusa (Gerv.). 



Hab.— United Provinces, I,ucknow ; Dr. N. ANNANDALE leg., 2i-iv-07. 

 Bengal, Calcutta, from Plumatella fruticosa and P. emarginaia in a 

 tank at the Zoological Garden ; Dr. N. ANNANDAI.E leg., S-i-oy. 



Nais ewnguis, Müi<Iv., OeRvST. 



Hab.— Punjab, Lahore ; Major J. STEPHENSON leg. 



Bengal, Alipur near Calcutta, edge of a pond, washed from colo- 

 nies of Plumatella emarginata ; Dr. N. ANNANDAI^E leg., i5-iv-o6. 

 Bengal, Calcutta, in Spongilla carter i ; Dr. N. ANNANDALE leg., 

 3i-viii-o6. 



Nais paraguayensis, Michi^sn. 



Hab,— Bengal, Calcutta, Museum tank ; Dr. N. ANNANDALE leg. 



Bihar, Sirsiah in the Mozaffarpur district ; E. BERGTHEIL leg. 



Remarks. — The Indian specimens of this species seem to differ in a slight degree 

 from the type specimens from Paraguay. As only the single specimen from Calcutta 

 is in a good state of preservation, I have regarded only this latter in the following 

 discussion. It is about 10 mm. long, i.e., about twice as long as the largest of the type 

 specimens, and its segments are very much more numerous. I counted about 98 

 setigerous segments, about the last 34 getting shorter and shorter with the setae 

 smaller and smaller, finally disappearing at a considerable distance from the hinder 

 end of the body, which shows no more annulation. After segment 63 or 64 the body 

 seems to be a little narrowed and its walls somewhat darker, and just at this place 

 the rapid decreasing of the annulation and of the setae begins. Perhaps we must 

 regard this narrowed part of the body as a zone of budding. None of the 

 type specimens from Paraguay showed a zone of budding, but this is in correspondence 

 with the shorter stature, the largest of them having only 47 setigerous segments and 

 probably being not yet full grown. 



The anus is directed dorsally. The ventral part of the hinder end is some- 

 what prolonged and turned upwards. 



The dorsal setae always begin at segment 6. The longer prong at the distal 

 end of the bifid setae sometimes seemed to be bent somewhat towards the shorter prong, 

 but not distinctly so. 



