420 KNTOZOA. 



of the whole number, and lives between the fibres of the mus- 

 cles of the Hog, producing' the disease called measles, it is 

 small, and multiplies prodigiously in this disgusting disease, 

 penetrating into the heart, eyes, &c. Similar animals have, it 

 appears, been oi)scrved in certain Monkeys and even in Man, 

 but they are said to be never found in the Wild Boar *. 

 The AcRosTOMA, Le Sauvage, Ann. des Sc. Nat. is closely allied 

 to this genus. The animal inhabits the amnios of the Cow. 



CCENURUS, Bud. 

 Here we find several bodies and heads adhering to the same bladder. 

 C. cerehraiis; Tcenia cerebralis, Gm. ; Gcetz., XX, A, B; 

 Encyc, XL, 1 — 8. This celebrated species is developed in the 

 brain of Sheep, destroys a portion of its substance, and pro- 

 duces a disease called the Staggers (Journis^, because it compels 

 them to turn on that side as if affected with vertigo. The same 

 species has been observed in the Ox and other Ruminantia, 

 where it produces similar effects. Its bladder is sometimes as 

 large as an e^^, and its parietes are thin, fibrous, and exhibit 

 evident contractions. The little worms are hardly half a line in 

 length, and re-enter the bladder by contraction f . 



ScoLEX, Midi., 

 Where the body is round, pointed behind, extremely contractile, 

 and terminated before by a sort of variable head, round which are 

 two or four suckers, sometimes resembling ears or ligulae. Those 

 that are known are very small, and inhabit fishes %. I have seen a 

 large one. 



S. g'njas, Cuv. ; Gymnorhynchus reptans, Rud., Syn., 129, 

 which penetrates into the flesh of the Sparus rait,h. The middle 

 of its body is inflated into a bladder, which, during the life of 

 the animal, alternately widens and contracts in the middle. 



FAMILY IV. 



CESTOIDEA. 



The fourth family comprises those Avhich are destitute of external 

 suckers. 



But one genus is known. 



LiGULA, Block. 



Of all the Entozoa, these appear to be the most simply organized. 

 Their body resembles a long riband ; it is flat, obtuse before, marked 

 with a longitudinal stria, and finely striated transversely. No ex- 

 ternal organ whatever is perceptible, and internally we find nothing 

 but the ova, variously distributed in the length of the parenchyma. 



* For the remraning species, see Rud.,Ent., II, p. ii, p. 215, and EL, 179. 

 t Here should probably come the genus Echinicoccus, Rud., II. p. ii. 247, but 

 I have not seen it, and have no idea of it sufficiently clear to enable me to class it. 

 X See Rud., Hist., II, p. 3, and Syn., 128. 



