Introduction to Animal Jforphology. 65 



are close together : one slender, shorter, and im- 

 movable ; the other, stouter and movable. The latter 

 becomes detached, and looks like a nematode, and the 

 rest of the body also elongates into a worm-like form. 

 (These pseudo-filariae have, perhaps, been taken for 

 nematodes by Bnich and Lcydig.) Both these worms 

 dilate at one end, and narrow at the other ; their 

 movements slacken, a nucleus and nucleolus appear, 

 and an outer membrane forms : thus Fig. 5. 

 they become perfect Gregarines. 



They are found in the intestines of 

 Invertebrates, chiefly Arthropods,rarely 

 in Vertebrates. Allied forms called 

 Psorospermia may be stages of un- 

 known Gregarines, and consist of 

 spindle or pear-shaped cells, often 

 tailed, with clear rounded bodies 



. , , , B. Pixinia rubecula. 



their smaller end, and a protoplasm c. Psemi<>navi<viia of 



/vfjfocystis sp. 



mass which sometimes is emitted as D- Amoebi'form stage. 

 an amcebiform body. They occur abundantly in the 

 muscles, &c., of Fishes and other Vertebrates. 



Two families exist: i. Monocystidea (Stein), with one 



partment and a central nucleus; including Mono- 



found in worms (Fig. 5, A), the valves of the 



human heart, human kidney, pine-wood, beetles, Kunu , 



. &c. 2. Dicystidea, having two compartments, 



with a septal layer of ectosarc between, and the nucleus in 



r; including Stylorhynchus, with hooks round the 



und in C'alo; Didymophyes, with three parts, 



and hind body; Actinocephalus, with spines 



round the head ; (in-.^arina, \\ith no hooks found in F.pheinera 



I.*.' 1 \inia, with honks and a head .separate (Yum 



the frnnt ^e-inent of the i II). 



and /> >hn\\n that gre.^ariniform 



liinorhyiirhus 

 :ia miliaria and ilillhiens). 



i 



