GENUS SPUMELLA. 305 



According to Cienkowski * this species plunders the contents of Volvox globator 

 in a manner somewhat identical with that pursued by Colpodella pugnax with relation 

 to Chlamydomonas pulvisculus. Boring its way through the outer envelope of that 

 protophyte, it creeps about on its inner surface, gradually devouring all the green 

 cellular elements and daughter-cells. During the process it presents a semi- 

 amoeboid aspect, but retains the two long natatory flagella; under these auspices 

 it would seem to exhibit more affinity with the genus Mastiganuxba, and might 

 therefore perhaps be appropriately relegated to the order of the Rhizo-Flagellata. 

 Subsequently the flagella are completely withdrawn and the animalcule forms a 

 double-walled encystment, the further development of which was not followed. 



C. PANTOSTOMATA-POLYMASTIGA 



(Flagellate appendages three or more in number). 



ram. xin. SPUMELLID^EJ, s. K. 



Animalcules naked, free-swimming or attached ; flagella terminal, three 

 in number, unequal, one long and two short ; no distinct oral aperture. 



GENUS I. SPUMELLA, Cienkowski. 



Animalcules minute, sometimes free-swimming but normally attached 

 by a slender thread-like pedicle, more or less spherical or ovate in their 

 sedentary state, but exceedingly plastic and changeable in shape in their 

 free-swimming condition ; flagelliferous system consisting of one long and 

 two short rudimentary flagella which originate close to each another near 

 the centre of the anterior border ; endoplast and one or more contractile 

 vesicles usually conspicuous ; no distinct oral aperture, solid food-particles 

 being incepted at all parts of the periphery. Inhabiting fresh and salt 

 water, and abundant in infusions. 



Those forms only are retained as representatives of the "present genus that 

 correspond structurally with the Spumella vulgaris of Cienkowski \ (Monas guttula 

 Ehr.), characterized by the possession of one long and two comparatively minute 

 flagellate appendages. The monoflagellate types referred to it by O. Biitschli, under 

 the titles of Spumella termo and S. neglecta, are necessarily relegated to the generic 

 group Oikomonas, with whose representatives, as also with those of Physomonas and 

 Amphimoiias, except strict attention is paid to the character of the flagelliferous 

 elements, the several species of Spumella are liable to be confounded. 



Spumella guttula, Ehr. sp. PL. XIV. FIGS. 46-52. 



Body perfectly globose in its sedentary condition, ovate, pyriform or 

 elongate in its free-swimming state ; flagellate appendages consisting of one 

 long and two very short rudimentary flagella, the former extended rigidly 

 and arcuately, the latter tremulous ; endoplasm transparent, finely granulate, 

 enclosing near the anterior border a short, straight, linear, pigmentary, or 

 more densely granular band ; contractile vesicle single, located near the 



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

 t " Ueber Palmellaceen und einige Flagellaten," ' Archiv f. Mikroskopische Anatomic,' Bd. ii., 

 1870. 



