F.NTOZOA. 



ill 



multitude of agglomerated cells mingled witli 

 tubes. The whole of these hollow unpins, the 

 parirtrs of which arc oxlrcmrU thin, and which 

 contain fluids the densities nl 'which \ary, nc- 

 cessanly make mutual exchanges of their con- 

 tents by way of endosmosis and exosmosis. 

 Nor can we suppose but that the same phi'iio- 

 iiicna take place among the various cells :>ud 

 cavities exhibited by the organism of animals. 

 Hut the effects of endosmosis, its influence on 

 the physiological phenomena pretented by ani- 

 mals, has yet to be determined ; and here, un- 

 doubtedly, the physiologist hits an ample field 

 before him for inquiry. I shall only say in 

 conclusion, and with reference to this very in- 

 teresting part of the subject, that I have satis- 

 lied myself that it is to endosmosis that the 

 motions of the well-known spiral spring tubes of 

 the milt of the cuttle-fish, when put into water, 

 arc owing. 



(U. Dutroc/iet.) 



ENTOZOA, (fro(, intus, /o, animal,) 



fXutvGs; crT^oyyt/Xot, iX/AlvOft -TrXarna*, acrxa- 

 jiJt, Arist. et Antiq. I'crs Inti-stinaux, Cuv. 

 Kiitflniintlia, SptantJtnelmint/M, /.eder. 



The term ENTOZOA, like the term Infusoria, 

 is indicative of a series of animals, associated 

 together chiefly in consequence of a similarity 

 of local habitation : which in the present class 

 is the internal parts of animals. 



In treating therefore of the organization of 

 these parasites, we are compelled to consider 

 them, not as a class of animals established 

 on any common, exclusive, or intelligible cha- 

 racters, but as the inhabitants of a peculiar dis- 

 trict or country. 



They do not, indeed, present the types of so 

 many distinct groups as those into which the 

 naturalist finds it necessary to distribute the 

 subjects of a local Fauna, yet they can as little 

 be regarded as constituting one natural assem- 

 blage in the system of Animated Nature. 

 And it may be further observed that as the 

 members of no single class of animals are con- 

 fined to one particular country, so neither are 

 the different natural groups of Entozoa exclu- 

 sively represented by species parasitic in the 

 interior of animal bodies. Few zoologists, we 

 ppnhead) would dissociate and place in sepa- 

 rate classes, in any system professing to set 

 forth the natural affinities of the animal king- 

 dom, the Plunnrite from the Tremaloda, or the 

 Vibrionida from the microscopic parasite of the 

 human muscles. 



In the present article it is proposed to divide 

 the various animals confounded together under 

 the common term of Entozoa or Entelmintha 

 into three primary groups or classes; and, as in 

 speaking of the traits of organization common 

 to each, it becomes not only convenient but 

 necessary to have terms for the groups so 

 spoken of, they will be denominated Pratcl- 

 minllia, Sterctmintha, and (.'itltimintha respec- 

 tively. 



It may be observed that each of these 

 groups, which here follow one another in the 

 order of their respective superiority or com- 

 plexity of organization, has been indicated, 



and more or less accurately denned hy ],r, 

 vious zoologists. Alter tin? dismcinlx-rnirnt 

 of the Infusoria of Cuvier into the classes 

 l'oli//ftistrica and RutiJ'era, which retulird 

 from the researches of ProfesMu I'.hri-nberg 

 into the structure of these microscopic beings, 

 there remained certain families of Animalcules 

 which could not be definitely classed with 

 either: these were the Ccrcariuda and Vibrio- 

 niii,, . Mr. 1'ritchard, in his very useful work 

 on Animalcules, has applied to the latter fa- 

 mily the term MoMO) from the analogy of 

 their external form to the ordinary species of 

 intestinal worms ; and it is somewhat singular 

 that a species referrible to the Vibrumul<c 

 should subsequently have been detected in the 

 human body itself. Premising that the tribe 

 Vibrionida as at present constituted is by no 

 means a natural group, and that some nf the 

 higher organized genera, as Angnillulii, are re- 

 ferrible to the highest rather than the lowest of 

 the classes of Entozoa, we join the lower organ, 

 ized genera, which have no distinct oviducts, ami 

 which, like the parasitic Trichina, resemble the 

 foetal stage of the Nematoid worms, with the 

 Cercariadte, in which the generative apparatus 

 is equally inconspicuous; and these families, 

 dismembered from the Infusoria of Lamarck, 

 constitute the class Protelmintha, the first 

 or earliest forms of Entozoa. 



The second and third classes correspond to 

 the two divisions of the class Intettinalia, in 

 the ' Itegne Animal ' of Cuvier, and which are 

 there respectively denominated ' Vers Intesti- 

 naux Parenchymateux,' and ' Vers Intestinatix 

 Cavitaires.' The characters of these classes will 

 be fully considered hereafter; and in the mean- 

 while but little apology seems necessary for in- 

 venting names expressive of the leading distinc- 

 tion of each group as Latin equivalents for the 

 compound French phrases by which they have 

 hitherto been designated. EX/xi( appears to 

 have been applied by the Greeks to the in- 

 testinal worms generally, as Aristotle speaks 

 of iXfxi6i; TrXariiai, intestinalia lata, and 

 ifyu9t( oTjoyytXat, intestinalia teretitt. In 

 framing the terms Sterelmintha and Calclmin- 

 tha, from iXpir; orijia, a solid or parenchy- 

 matous worm, and ttyu; xoiXn, a hollow or 

 cavitary worm, I follow the example of Zeder, 

 and omit the aspirate letter. It may be ob- 

 served by the way that Zeder's term Splanchnel- 

 mintlia, besides including animals which are 

 developed in other parts than the viscera, is. 

 like the terra Entozoa, open to the objection of 

 being applied to a series of animals which, ac- 

 cording to their organization, belong to distinct 

 classes. 



The limits and object of the present article 

 obviously forbid an extensive or very minute 

 consideration of the anatomical details of each 

 of these classes of animals, and we are com- 

 pelled to confine ourselves almost exclusively 

 to such illustrations of their respective plans 

 of organization as are afforded by the species 

 referrible to each which inhabit the human body. 

 If a drop of the secretion of the testicle be 

 expressed from the divided vas deferens in 

 a recently killed mammiferous animal, which 



