11'2 THE AMERICAN MONTHLY [May, 



On the Occurrence in the Fresh-waters of Calcutta of Reticu- 

 lated Ani(jBba. 



By W. J. SIMMONS, 



CALCUTTA, INniA. 



The organism probably identical with Biomyxa vagans^ Leidy, from 

 the fresh-waters of North America, consists of a glairy, colorless, 

 and finely granular protoplasm, similar to that observable in Amcebm 

 and other Rhizopods. In Biomyxa this protoplasm exhibits a marked 

 tendency to bipolarity, that is to say, its pseudopodia, as the extensions 

 of its bodily substance which subserve locomotion are called, are ex- 

 tended from opposite poles as fine threads, which anastomose with 

 one another so as to form an irregular network with knot-like expan- 

 sions at the points of intersection of the threads, which expansions are 

 comparable in all respects, save size, to the main mass. The organism 

 changes in form from moment to moment, when in full activity. Mr. 

 Wood-Mason had suggested to me that the nucleus, which the writer 

 had not detected, might have been left behind in the web of the 

 pseudopodial network, or more probably been concealed by the gran- 

 ules and ingested food particles. Along the glassy threads of this 

 network solitary or associated granules course at a rate which, when 

 most active, exceeds that of cyclosis, as observable in such a plant as 

 Vallisneria^ the flow being in opposite directions on the two margins 

 of the filaments ; while fusiform particles of protoplasm glide down 

 the pseudopodia like rain-drops along an inclined telegraph wire. Mi- 

 nute vacuoles present themselves both in the main mass of the organism 

 and in the knot-like expansions of the pseudopodial filaments. There 

 is no visible distinction between the exoplasm and the endoplasm. 

 Three or four diatoms ( Cocconcis^ Sp.) were seen to be imbedded 

 in the main mass of the protoplasm, and several Flagellata were 

 being towed along the pseudopodia, their flagella having appar- 

 ently been caught in the current of protoplasm flowing in the reticu- 

 lated filaments. Some Bacteria were also observed, and it seemed 

 obvious that they too were being swept along owing to their flagella 

 adhering to the protoplasm in the filaments. The organism is doubt- 

 less identical with Leidy's Biomyxa vagans. It was found amidst the 

 debris of a decaying leaflet of Anarcharis obtained from a bowl of 

 water and weeds which was drawn from General's Tank on the ist of 

 February last, and has been under observation from that day onwards 

 throughout the month of February, the specimen of Biomyxa^ having 

 been observed on the 22d idem. Four drawings were made with the 

 aid of Beck's vertical camera. The first sketch was drawn about 9 

 o'clock ; the second and third about noon, when the organism had at- 

 tained its fullest development and activity ; the last sketch was drawn 

 a little after 4 o'clock, by which time the organism had shrunk consid- 

 erably, and nodules of protoplasm had commenced to form themselves 

 on the central body, while the flow of granular matter had become 

 vei-y feeble. Adopting the most recent classification, the systematic 

 position of -5'/c>7?/j':va, according to Biitschli, would be: Rhizopoda; 

 sub-order i, Amoebcea ; Family Amoebcca rctic7ilosa ; Genus Biomyxa 

 (Leidy) — of which at present but one species had been found in the 

 fresh-waters of North America, and, we must probably add, of India.. 



