GENUS HYMENOMONAS. 



Chlorangium stentorinum, Ehr. sp. WOODCUT, FIGS. 1-7. 



407 



Bodies elongate-ovate or subfusiform, about three times as long as 

 broad ; flagella terminal, subequal, not so long as the body ; endoplasmic 

 colour-bands bright green, produced throughout the whole extent of the 

 two lateral borders, one of these including near its distal end an obscure 

 eye-like pigment-spot ; contractile vesicle situated at the anterior ex- 

 tremity, close to the insertion of the flagella ; endoplast spherical, sub- 

 central, attached during the sedentary condition to a short, simple, or 

 slightly branching pedicle, in groups of from two or three to ten or twelve 

 zooids. Length of zooids 1-1150". 



HAB. Pond water, on various Entomostraca. 



Chlorangium ttentortKum, Ehr. sp. i. Free-swimming biflagellate zooid ; c v, contractile vesicle ; e, eye-like 

 pigment-spot ; , nucleus or endoplast. 2. Encysted zooid attached by a stalk-like prolongation of its anterior extre- 

 mity. 3 and 4. Encysted zooids, with body-substance separated respectively into two and four segment-masses. 

 5. Further developed stage of the preceding example, in which the four segment masses having burst the cyst wall, 

 remain attached distally to the parent pedicle ; at a, residual portion of the primary cyst. 6. Adult sedentary colony- 

 stock, produced through the further subdivision of the zooids represented in the preceding figure. 7. Single encysted 

 zooid, whose body-mass has become subdivided into minute sporular elements. (After Stein, X 480.) 



This species was first described by Ehrenberg under the title of Stentor (fypygmaus, 

 but is relegated in his subsequent work, ' Die Infusionsthierchen,' to the genus 

 Colacium. The grounds upon which it has been found necessary to separate it 

 from this last-named' generic group, have been already indicated. The growth of 

 the sedentary arborescent colony-stocks of this animalcule are produced, according 

 to Stein's recently published volume, and as shown in the accompanying woodcut, 

 by the endogenous subdivision of a primary attached zooid, whose cuticle finally 

 bursting exposes the internally developed units, each with its anterior extremity 

 firmly attached to the extremity of the parent pedicle. A portion of the posterior 

 region of the parent cuticle frequently remains for a considerable interval embracing 

 the base of the common stock and presenting, as seen in profile, Fig. 50, the aspect 

 of two lateral setose processes. Sporular multiplication, in which encysted zooids 

 attached singly to their pedicles become divided up into a number of minute micro- 

 spores, as shown at Fig. 7, is also placed on record by the authority just quoted. 

 A distinct oral aperture has apparently as yet not been detected, but probably 

 exists and corresponds with that possessed by Colacium. 



GENUS IX. HYMENOMONAS, Stein. 



Animalcules solitary, free-swimming, secreting a more or less flexible 

 lorica ; flagella two in number, subequal ; lateral pigment-bands con- 

 spicuously developed ; no eye-like speck ; contractile vesicles anteriorly 

 located. Inhabiting fresh water. 



