58 GENERAL ORGANIZATION OF THE PROTOZOA 



Genus 3. Selenidium, Giard, 1884; emend Caullery et Mesnil, 1899. The body 

 is attenuated and worm-like, and marked externally by longitudinal stria- due 

 to the ectoplasmic myonemes. Epimerite conical and slender. Parasites of 

 polychetes and numerous species are recorded. 



Suborder 2. EUGREGARIN^E, Leger. Reproduction here is limited apparently to 

 sporulation, division occurring, if at all, within the host cell and during the 

 young stages. 



Tribe I. Acephalince, Kolliker. Eugregarines in which there is no division into 

 chambers and in which at no stage is there an epimerite. 



Genus 4. Monocystis, Stein, 1848. The trophozoites are often highly contractile 

 owing to the peristalsis brought about by the contractions of ectoplasmic 

 myonemes. Spores boat-shaped and octozoic. Many species from worms and 

 entomostraca, a typical species, M. agilis may be found almost invariably in 

 the seminal reservoirs of the common earthworm, and excellent stages in 

 sporulation and fertilization may be easily obtained. 



Genus 5. Zygocystis, Stein, 1848. The trophozoites are usually found in pairs or 

 groups of three. Typical species, Z. cometa, Stein, found in the seminal 

 vesicles and body cavity of the earthworm Lumbricus agricola. 



Genus 6. Zygosoma, Labbe, 1899. The trophozoite has typical and characteristic 

 finger-like processes and is usually found in couples. Sporulation unknoivn. 

 Typical species, Z. gibbosum, Greeff, 1880, in the gut of Echiurus pallassii. 



Genus 7. Pterospora, Racovitza and Labbe, 189(3. The piriform trophozoites 

 are always associated in couples. The spores have dissimilar poles and the 

 epispore is drawn out into lateral processes. One species, P. maldaneorum, 

 R. and L., from the celomic cavity of maldanid worms. 



Genus 8. Cyxtobia, Mingazzini, 1891. The trophozoites are large and irregular 

 in form and usually have two nuclei due to the early fusion of two individuals. 

 The spores are heteropolar, and the epispore is drawn out into chimney-like 

 projections at one pole. One species, C. holothuriae, A. Sch., from the blood- 

 vessels and body cavity of holothurians. 



Genus 9. Latkocysiis, Giard, 187(3. The trophozoite is characterized by an endo- 

 plasm filled with crystals of calcium oxalate. The epispore has long pro- 

 cesses. A single species from the ccelomic cavities of various echinids. 



Genus 10. Ceratoxpora, Leger, 1892. The trophozoites fuse by their truncated 

 ends and give rise to spores without encysting. The spores are character- 

 ized by long spinous processes (Fig. 20). A single species, C. mirabilis, 

 Leger, from the body cavity of Glycera. 



Genus 11. Urospora, A. Schn., 1875. The spores are characterized by the presence 

 of a long caudal filament at one pole. Several species from the body cavities 

 of oligochetes, nemertines, sipunculids, and other marine invertebrates. 



Genus 12. Gonospora, A. Schn., 1875. The trophozoites are quite variable in 

 form and give rise to heteropolar spores bearing from one to several tooth-like 

 processes at one pole, and rounded at the other. Four species from the body 

 cavities of polychetous worms. 



Genus 13. Syncystis, A. Schn., 1886. The spores are ovoid or boat-shaped, with 

 spines or processes at each extremity. One species, S. mirabilis, A. Schn., 

 from fat body and ccelom of species of Xepa. 



Genus 14. Diplocystis, Kunstler, 1887. The trophozoites fuse precociously to 

 form spherical masses of gregarines in the body cavity of crickets and cock- 

 roaches. The spores are either spherical or oblong. 



Genus 15. Lnnkesteria, Mingazzini, 1891. The spores are more or less flattened 

 or spatulate, oval in outline, and octozoic. Type species, L. ascidite, Lank, 

 from the gut of Ciona intestinalis. 



Genus 16. CaUyntroclilamyi*, Frenzel, 1885. The trophozoites have a central 

 constriction but no septum dividing the body into protomerite and deuto- 



