ENTOZOA. "■ 117 



observed, that the flesh of fishes in summer is often studded with 

 small worms, which, in one instance, he ascertained to be Echino- 

 rhynchi; and he suggests whether it may not be the breeding-place of 

 such species, and whether the Trichina spiralis may not belong to 

 the same category. But how these embryos (if they be embryos) are 

 diffused through the intermuscular cellular tissue, can only be known 

 after long and laborious investigations ; and nothing is more true than 

 that a particular inquiry will be required for each particular species. 



Summary of the Classes, Orders, and Families of the Entozoa of 

 lludolphi : — 



Class STERELMINTHA. 

 The nutrient canals or cavities excavated in the parenchyme of 

 the body. 



Order Tjenioidea. 

 The head provided with two, four, or six acetabula, and usually 

 with spines, either sessile or placed on a proboscis, or on tentacula. 



Family Cystica. 

 No organs of generation ; body terminated by a bladder filled with 

 fluid. (All are, probably, taenioid larvae.) 



Genera : Echinococcus, Ccenurus, Cysticercus. 



Family Scolecidje, 



Body short, or moderately long ; sometimes partially vesiculated, 

 usually encysted ; no generative organs. (All are, probably, larvje.) 



Genera : Anthocephalus, Dibothriorhynchns, Floriceps, Gymno- 

 rhynchus, Hepatoxylon, Rhynchobothrixim, Scolex, Tentacularia, 

 Tetrarhynchus (many species). 



Family Ligvlidje. 

 Acetabula and spines obsolete ; body solid, depressed, long, with a 

 longitudinal furrow, not jointed, but finely striated transversely. 

 Genus : Ligula. (Those of fishes are, probably, larvae.) 



Family Cestoivea. 



Body long, depressed, jointed, with male and female organs com- 

 bined in each of the mature segments. 



Genera : Tetrarhynchtts (certain species), Bothriocephaltis, Tania, 

 Caryophyllceus. 



Order Trematoda. 

 Body generally depressed, not jointed, with one or more acetabula ; 

 mouth an unarmed pore, from which a bifurcate or branched alimen- 



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