296 ORDER FLA GELLA TA-PANTOSTOMA TA. 



Heteromita exigua, Perty. 



Body oval or spheroidal, transparent ; flagella about three times the 

 length of the body, one projecting in front, the other trailing. Length 

 1-7200" to 1-4800". 



HAB. Turf water, in the Bernese Alps. Movements oscillating. 



It is almost impossible to decide from the brief account given by Perty, whether 

 this species is an independent form or only the young of another animalcule. 



Heteromita pusilla, Perty. 



Body elongate-ovate, subcylindrical, more or less constricted centrally, 

 sometimes emarginate posteriorly ; flagella from two to two and a half 

 times the length of the body ; endoplasm slightly granulate ; movements 

 oscillating. Length 1-3600" to 1-2160". 



HAB. Stagnant water with Conferva. 



Heteromita amyli, Cienkowski sp. 



Body elongate-fusiform, pointed at each extremity, seven or eight times 

 as long as broad ; flagella fine, subequal, not quite as long as the body. 

 Length 1-600". HAB. Pond water with decaying Nitella. 



This species, originally described by Cienkowski under the name of Monas 

 amyli* must necessarily be separated from the genus Monas on account of its pos- 

 sessing two flagellate appendages. The comportment and proportions of these organs 

 in accordance with that writer's drawings, correspond furthermore so closely with 

 those of the ordinary representatives of the present genus, that it appears desirable to 

 retain it in the same. The assumption of an amoeboid phase accompanied by the 

 extension of slender ray-like pseudopodia was witnessed, as also the fusion or 

 coalescence of numerous animalcules into a single mass during their amoeboid state 

 after the manner of Heteromita uncinata previously described. The result of this 

 conjugative process was the formation of a spheroidal cyst, the contents of which 

 split up into innumerable fragments to be subsequently released as monadiform germs. 

 The presence of a spherical endoplast and one or more contractile vesicles was 

 noted during the amoeboid phase. Excepting that this animalcule is not reported to 

 possess the faculty of assuming a spirally twisted contour, its general form and 

 proportions correspond closely with those of the Heteromita (Spiromonas) angiistata 

 of Dujardin hereafter described. 



Heteromita sulcata, Mereschk. 



Body somewhat variable in form, more or less oval or cylindrical, about 

 twice as long as broad, the hinder extremity rounded or evenly truncate, the 

 anterior border obliquely truncate ; the dorsal surface traversed throughout 

 by three or four parallel longitudinal furrows or striations ; flagella slender, 

 subequal in size, the posterior or trailing one slightly the longer, not twice 

 the length of the body ; contractile vesicle single, of large size, situated 

 close to the insertion of the flagella. Dimensions unrecorded. 



HAB. Fresh water : Northern Russia (Mereschkowski t). 



* " Beitrage zur Kenntniss der Monaden," ' Archiv fur Mikroskopische Anatomic,' Bd. i., 1865. 

 t " Studien iiber Protozoen des Nordlichen Russland," ' Archiv fur Mikroskopische Anatomic,' 

 Bd. xvi., 1878. 



