Neto Hifpotrichous Infusoria from Calcutta. 249 



beyond the posterior margin ; three on the left side are arranged in 

 an oblique, and two on the right side in a transverse row. The 

 marginal cirri are long, and arise from the ventral surface just 

 inside the lateral margin ; those on the right side extend along the 

 entire margin, while those on the left side extend from the middle 

 and stop short of the posterior end. The macronuclei are two and 

 oval in shape, each with a micronucleus ; the anterior one is placed 

 anteriorly, while the posterior one is placed just behind the middle 

 of the body. One contractile vacuole is placed in the middle of 

 the body and near the right lateral margin. Lt. 0'063 mm. Br. 

 0-02 mm. 



The animalcules were found in large numbers in vegetable 

 infusion. 



The present animalcule undoubtedly belongs to the sub-family 

 Psilotrichinfe, in having a small body and in the great reduction 

 and irregular arrangement in the number of and irregular arrange- 

 ment of the cirri. 



It resembles the two S]iecies of Balladina Kowalewski, in 

 having a rigid body, in elongated marginal cirri, in the absence of 

 frontal cirri, in the number and arrangement of anal cirri, in the 

 somewhat elongated membranelles, in the number of macro- and 

 micronuclei, and in having a single contractile vacuole. It, how- 

 euer, differs from them, B.parvula Kowalewski (Biol. Centralb., Bd. 

 Ill, 1883), and B. dongata Roux (Rev. Suisse Zool., T. VI, 1899), 

 in the absence of a single row of ventral cirri, not differentiated 

 into frontal and abdominal, and extending from near the anterior 

 end of the body to the anal cirri parallel to and at a little distance 

 from the right lateral margin (an important characteristic of the 

 genus Balladina), and in the absence of bristles on the dorsal 

 surface. 



Aspidiscopsis hengalensis g. et sp. n., fig. 2. 



The body is broadly ovate, narrow and tapering to a rounded 

 end in front, and broadly and obliquely subtruncate behind. The 

 riglit margin is evenly convex. The left margin presents a shallow 

 notch just behind the anterior end, but is uniformly convex behind 

 the notch. The notch is produced into a groove on the ventral 

 aspect. The dorsal surface is convex and presents six or seven 

 longitudinal ribs. The peristome is an obliquely crescentic area 

 occupying the posterio-lateral portion of the ventral surface abut- 

 ting on the left margin and extending about half its length. 

 There are about eight membranelles in the peristome. The frontal 

 cirri are four in number and are placed just in front of the notch. 

 The abdominal cirri are five in number. Of the first two cirri, one 

 is placed behind the notch and the other further behind and 

 median wise ; the next two are stout and lie side by side ; the fifth 



