378 ORDER FLAGELLATA-EUSTOMATA. 



Astasia defor7nis, From. — Body hyaline, with irregular digitate expan- 

 sions ; contractile vesicles posteriorly situated. Length 1-600". 



Astasia turbo, From. — Body top-shaped, with a dilated, somewhat 

 flattened central portion, and attenuate anterior and posterior regions ; 

 parenchyma finely granulate ; flagellum long and slender. Length 

 1-400". 



Astasia fusiformis, From. — Body fusiform, attenuate at the two extre- 

 mities ; contractile vesicle conspicuous, posteriorly situated. Length 

 1-600". 



Astasia crassa, From. — Body highly contractile, subspherical, often 

 changing its form, but retaining an attenuate, tail-like, posterior prolon- 

 gation ; flagellum long and slender ; parenchyma white and granular. 

 Length 1-700". 



Astasia regular is, From. — Body regularly oval, slightly flattened on one 

 side ; pharyngeal tract conspicuous ; parenchyma enclosing coloured granules. 

 Length i-iooo". 



The TracheUus deiidrophilus of Ehrenberg * — " body ovate, subacute at each 

 extremity, proboscis fiagelliform, slender and pointed, more than twice the length of 

 the body. Length 1-3456"." Found among moss from trees, with habits like those 

 of Trac/ielius {Astasia) trichophora — is apparently a minute representative of the 

 present genus. 



Genus IL COLPODELLA, Cienkowski. 



Animalcules free-swimming or adherent, ovate or elongate, bearing a 

 single anterior terminal flagellum, at the base of which is a suctorial oral 

 aperture ; contractile vesicle and endoplast conspicuous. Habits predatory, 

 preying upon various minute Phytozoa, the cell-walls of which they perforate, 

 and abstract the contents. 



In contour and in the character of the single flagellate appendage the repre- 

 sentatives of this genus are scarcely to be distinguished from those of ATonas or 

 Para7Ji07ias, and might, unless observed in the act of feeding, be relegated to one of 

 these two genera. 



Colpodella pugnax, Cienk. Pl. XX. Fig. 22. 



Body somewhat variable in form, its most characteristic shape elongate, 

 semilunate, pointed at each extremity, with a flat ventral and convex dorsal 

 border ; flagellum equalling or slightly exceeding the body in length ; con- 

 tractile vesicle single, circular, situated close to the ventral border at a short 

 distance from the posterior extremity ; endoplast spherical, anteriorly 

 located. Length 1-2000". 



Hab. — Fresh water, preying upon Chlamydomojias pidvisculus. 



According to Cienkowski j" the zooids of Colpodella pugnax, after fully satis- 

 fying their hunger by the extraction of the cell-contents of one or more speci- 

 mens of the above-named protophyte, become encysted, and the enclosed bodies 

 split up into eight or more sporular elements. These subsequently make their 



* 'Ber. Akad. Berlin,' 1853. 



t ' Archiv fiir Mikroskopischer Anatomic,' Bd. i., 1865. 



