54 



PROTOZOA. 



alike and knobbed, arranged in tufts, which may be numerous and placed at 

 the ends of branch-like lobes. Trichophrya Clap, and L., Dendrosoma Ehrb. , 

 large animal resembling a colony, with branched niacronucleus extending 

 throughout the body. 



Fam. 7. Dendrocometina. Sessile, with numerous knobbed tentacles on 

 branched arms or over the whole free surface. Attached by the whole basal 

 surface or by a part of it. Dendrocomeles Stein, gills of Gammarus pulex ; 

 Stylocometes Stein, on gill-plates of Asellus aquaticus. 



Fam. 8. Ophryodendrina. With short or long stalk, tentacles rarely 

 distinctly knobbed, and borne by one to several proboscis -like processes of 

 the body. Ojihryodendron Clap, and L. 



Class III. SPOKOZOA.* 



Parasitic Protozoa 

 H-liirh reproduce by spore- 

 formation. Nutriment is 

 talci'n up in the liquid 

 tfate. In most, jirobably 

 in all, the young stages at 

 least are intracellular in 

 habit. 



The Sporozoa are found 

 in all the great groups of 

 animals except the Proto- 

 zoa and Coelenterata. In 

 the young state at least 

 they live embedded in the 

 protoplasm of their host, 

 into which they make 

 their way when hatched 

 out from the minute 

 spores. They are there- 

 fore described as intra- 

 cellular parasites. In 

 some forms they remain 



within the cell throughout life, but more often they outgrow 

 the cell and come to lie free in the tissues or spaces of the body. 

 They live entirely on the nutritive juices of their host, and their 

 power of movement is limited. Some have little or no power of 



* Balbiani, Lecons sur les Sporozoaires, Paris, 1884. Biitschli, "Sporozoa," 

 in Bronn's Klassen u. Ord. d. Thierreichcs, 1880-82. L. Pfeiffer, Die Protozoen 

 als Krcmkhcitserrcger, ed. 2, Jena, 1891, and Nachtrdgc, Jena, 1895. Idem, 

 Die Zellerkrankungcn etc. durch Sporozoen, Jena, 1893. V. Wasielewski, 

 Sporozoenkunde, Jena, 1896. 



FIG. 45. Gregarines (after Stein and Kolliker). a, 

 Stylorhynchvs oligacanthits from the intestine of 

 Calopteryx; 6, Gregarina (Clepsidrina) polymorphic, 

 from the intestine of the meal-beetle, two forms in 

 "association"; c, two forms of the same in conju- 

 gation ; d, encystment completed ; e, sporulation ; 

 /, cyst with completely formed spores (pseudo- 

 navicellse). 



