74 



SPOBOZOA. 



to the host by' means of sucker-like bodies borne on the ultimate 

 branches. Ectoplasm shows longitudinal and transverse 

 striations. The transparent fluid endoplasm is densely packed 

 with ovoid paraglycogen granules. Nucleus is a large ovoid 

 body containing a spherical eccentrically situated karyosome. 



Dimeiisions. — Trophozoite may be as long as 4 mm., nucleus 

 640-860 IX in length ; gametocysts about 620 ix in length ; 

 sporocysts of two sizes, the larger 20-23 yu, long, the smaller 

 7-9 /x long. 



Remarks. — The parasite presents a smooth creamy-white 

 appearance or, very rarely, a light brownish tinge. The large 

 unattached end is bluntly rounded. At a gTeater or less 

 distance from this end the body branches into two rami, 



Fig. 20.- 



-Aikinetocystis singularis Gates, n, nucleus ; K, karyosome ; 

 Pr, primary ramus ; Sr, secondary ramus. (After Gates.) 



each of which divides to form two smaller secondary rami, 

 This branching continues until eight or sixteen small ramuli 

 are produced. The dichotomy is regular. The ramuh bear 

 groups of irregularly ovoid, sucker-like objects by means of 

 which the parasite is attached to the host. Pairs of animals 

 are frequently found attached to each other near the rounded 

 free ends. Groups of three to eight animals, similarly adherent 

 to each other, are also found. 



Living detached specimens show two kinds of movements. 

 Waves of peristaltic contraction pass along the trmik and rami 

 of the first order, producing a churning of the endoplasmic 

 contents in the trunk, from the trunk into the primary rami, 

 and back into the trunk ; the nucleus is squeezed to and fro 

 from one end of the trunk to the other, or even passing into 



