Mr. H. J. Carter on a Freshwater Species o/Ceratium. 229 



XXVII. — Note on a Freshwater Species of Ceratium from the 

 Lalx-e of Nifnee {Naini) Tal in Kumaon. By H. J. 

 Carter, F.II.S. &c. 



Several species of horned Peridinea (viz. of Ceratiuyn) from 

 the Baltic Sea have been described by Ehrenberg and others, 

 while those called by the former C. tripos and C.farca have 

 been seen by MM. Pringsheim and Wemeck, respectively, in 

 fresh water also (Clap, et Lachm. '■ Etudes sm- les Infusoires ' 

 &c. vol. i. pp. 399 and 400). Perty (Zur Kenntniss &c. 

 p. 161, pi. 7. fig. 13) describes one, mider tlie name of G. lon- 

 fjicorne, from the Swiss lakes, where they are found; and, lastly, 

 we have them from the lakes of the Himalaya and Lower 

 Bengal. 



Thus my friend Dr. Forbes Watson, of the India Museum, 

 has submitted to me for re- 

 port a glass slide containing 

 several mounted in gum 

 from the lake of Nynec Tal. 



Of these, ]Mr. Stewart 

 Clark, Inspector-General of 

 Prisons, N.W.P., who for- 

 wards them, states that they 

 are " perfectly visible to the 

 naked eye, chiefly on the 

 surface, 10-15 feet down, 

 very few below 20 feet, and 

 })robably none at the very 

 bottom of the lake, which is 

 95 feet deep. 



" They are found in all 

 the lakes of Kumaon at an 

 elevation of from 4000 to 

 6500 feet above the level of 

 the sea. 



" The ordinary beautiful blue colour of the lake at Nynee 

 Tal was at their captm'C, and had been for some months 

 previously, changed to a rusty brown, by the presence of 

 myriads of this kind of Infusorium." 



The chief interest in the species is that, although it is closely 

 allied to G.furca^ Ehr., yet it must be regarded as a variety 

 of this form, inasmuch as the posterior horn in the figures of 

 the latter given by Ehrenberg (' Infusionsthier.') and Cla- 

 par^de (' Etudes '), respectively, is represented as smooth, while 

 in those forwarded from the lake of Nynee Tal (see figure) all 

 three of tlie horns are equally though minutely serrated by 



C'eratunn kumnonense, dorsal view, 

 maguified. (Scale l-24th to 1-GOOOth 

 of an incli.) a, portion of horn more 

 uia^jfuified, to show the disposition of 

 the tubercles; b, point from which the 

 fourth horn might be developed (?). 



