MORPHOLOGY AND TAXONOMY OF MASTIGOPHORA 2G5 



matrix in which they reproduce by division forming great colony- 

 Hke aggregates attached to water plants (Hydriiridae) or smaller 

 planktonic gelatinous masses. A simple contractile vacuole, a 

 single chromatophore, and single or double flagella are typical of 

 the individual monads. The group is rather artificial but very 

 interesting theoretically, with transition forms between motile forms 

 of flagellates and typical plants with apical growth {Hydrurus, Fig. 

 127). Two families are given in Pascher's classification: 



Family 1. Chrysocapsidae, Pascher. — Palmella-stages relatively 

 small gelatinous masses of varied form and with no evidence of 

 apical growth. Reproduction by division of monads which become 

 flagellated, leave the gelatinous matrix, swim freely for a time, then 

 lose the flagellum, become quiescent, secrete a gelatinous substance 

 and divide. 



Faviily 2. Hydruridae, Klebs.— Palmella-stage large, up to 30 cm., 

 usually cylindrical in form, and usually branched. The monads 

 are loosely arranged in the gelatinous matrix, a single one forming 

 the apex of each branch. With division of this apical cell one of the 

 products becomes apical while the other contributes to the thicken- 

 ing of the mass. The division products of all cells may at any time 

 develop a single flagellum and swim oft* in the form of a four-cornered 

 p^Tamidal flagellate (Fig. 127, C) with a single yellow chromatophore 

 and a leucosin mass. Characteristic cysts with silicious walls and 

 stopper are present. One genus and species II yd runts foetid its, 

 Kirschner (Fig. 127). 



Order II. CRYPTOMONADroA, Stein. 



The Cryptomonadida, like the Chrysomonadida, are small col- 

 ored flagellates which rarely measure more than 30 /j. (exceptional 

 species up to 80 /x) • They difter from Chrysomonadida in having a 

 constant body form with little tendency to form pseudopodia. 

 Many are laterally compressed and show a dorso-ventral dift'eren- 

 tation due to a median furrow which passes obliquely over the ante- 

 rior end, resulting in an arched dorsal and a flat ventral side. In 

 some types the furrow leads into a cup- or tube-shape depression 

 which may extend deep within the endoplasm as a c\^opharynx. 



Flagella are one or two in number and are frequently band-form 

 with a tapering extremity; if two are present one is usually thicker 

 than the other. They are inserted in the furrow or on the ventral 

 wall of the cytopharynx. 



The pellicle is simple and delicate in some forms but may be 

 heavy and provided with striations which have been questionably 

 interpreted as myonemes to which contractions of the body are due. 



Many forms are colorless but in the group as a whole chromato- 

 phores of yellow, brown, blue, blue-green and green color are present . 



