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Show 350 ENTOZOA. ORDER I. NEMATOIDEA, Rud.(l) Th' order compri·s es those whose external ski.n , md ore ot• IS • • h ular fibres, and usually striate trans-less furmshed ~It :~~~aminal cavity in which is a distinct versely, con tams a d' g from the mouth to the anus, and . t f nal canal ex ten m h f h In es I ' 11 b rve distinct organs in eac o t e where we genera t~ 0 ~e connected with the neighbouring The intes Ine IS sexes. 1 envelope of the body by numerous parts, and tl~~ g:~e~ some writers as vessels for the conthreads, consi er . . Y fluid and by others as trachere, but ce of the nutritious ' . v~yan roof of the fact. It is impossible to detect any witho~t any? . h animals but in several there appear true Circulation In t ese cords a~ising from a ring which sur-b e· or two nervous d to e on h d xtending the whole length of the bo y rounds the mout ' an e . ternal surface of the envelope. along t~e In . . nerally straight, and tolerably wide; the The mtestine IS ge · . f tl smaller and in some species we re-esophagus IS re~uen Y • goro;s stomach. The internal 01'· mark a larger ~n ~or~svti of extremely long vessels, contain· of generation cons1 . ginagns t he semen or t h e ova, which open at different p.o mts, ac· cording to the genus. FILARIA, Lin. l d filiform and perforated at Where the body is elongated, sen er, : The Filari~ in . t b a round oral apertUI e. the anterior extreml y y similar to the Gordii. They are their external appearance .a:e vefry . 1 hich do not open exter· chiefly found in those cantles o amma s w . 1 t ·a constitutes the EN· (1) This order, with the exception of the tw.o ~sl gener , TOMOZAIRES Al'ODES 0.X.YC£l'll.A.LES of !il· de Blamvil c. NEMA TOIDEA. . 351 nally, such as the cellular membrane, and even in the thickness of the membranes and the parenchyma of the viscera; there we some· times find th-em in bundles and countless numbers, enveloped in species of capsules. They are found in Insects and their larvre, and even in the visceral cavity of several Mollusca. The most celebrated species of this genus F. medinensis,Gm.; Encyc. XXXIX, 3 (The Guinea Worm), is very common in hot climates, insinuates itself under the skin of man, generally that of the leg, where, if credence be given to the reports of certain authors, it acquires a length of ten feet and more, may remain there several years without producing violent pain, or cause intense agony and excite convulsions, according to the nature of the part it attacks. When it shows itself externally, it is seized and extracted very slowly for fear of breaking it. It is about as thick as the barrel of a Pigeon's quill. Its pointed and hc;>oked tail constitutes its dis· tinguishing character( 1 ). · TRICHOCEPHALUS. Where the body is round, thickest posteriorly, and as slender as a thread anteriorly. This slender part is terminated by a round mouth. The most common species is the T. dispar, Rud.; Gretz., VI, I, 5; Encyc., XXXIII, I, 4. From one to two inches in length, of which the thickest portion forms but the third. This part, in the male, is spirally convoluted, and a little penis projects near the tail. It is straighter in the female, and simply perforated at the extremity. It is one of the most common Worms in the great intestines of Man, where, in certain diseases, it becomes prodigiously multiplied( 2). Naturalists have distinguished from the preceding the (1) FQr the other Filatire, see Rud., Ilist., II, 57, Syn., p. 1. N.B. Rudolphi, in his Synopsis, has suppressed the genus liAMULAnu., which was characterized by two little oval filaments. On examination, they were found to be the male organs of generation, placed at the posterior extremity. (2) For the Tricocephali of animals, sec Rud., Ent., II, 86, and Syn., p. 16. |
