CLASS V. 
INTESTINAL WORMS (£NT70ZO4)'. 
By Intestinal Worms are understood worms that live in other ani- 
mals, (not necessarily in their viscera). Though not more correctly 
in point of language, they might, perhaps, be better named Internal 
Worms, which would be a literal translation of the word Hntozoa. 
This class is by no means natural, for the animals included in it not 
only differ remarkably from each other in external form, but also 
in internal structure. The efforts that have been made hitherto to dis- 
tribute the different orders and families of the Entozoa amongst the 
different classes of invertebrate animals have not been satisfactory. 
In this, as in so many other attempts to determine the affinities of 
animals, a certain external resemblance has been mistaken for 
correspondence of internal structure and of type of organisation, by 
which alone true affinities can be established. An unprejudiced 
inquirer will scarcely attach more value to a comparison of Echino- 
rhynchus with Sipunculus, of Cysticercus with bladder-bearing 
Acalephs, &c. than to a comparison of bats with birds. Consequently 
we are compelled to retain the class Hntozoa, however we acknow- 
1 Compare on this class: 
C. A. Ruponput, Entozoorum sive Vermium intestinalium Historia naturalis, 11. 
Tomi, c. tab. en. Amsteledami, 1808—ro, 8vo. 
C. A. Rupotrut, Lntozoorum Synopsis, cui accedunt Mantissa duplex et indices 
locupletissimi, c. tab. 111. en. Berolini, 1819, 8vo. 
Dr. Bremser, Ueber lebende Wiirmer im lebenden Menschen. Mit tv. illum. Kupfert. 
Wien, 1819, 4to. 
BremseEri Jcones Helminthum. r11. Fasciculi. Vienne, 1823, folio. 
J. Croqurt, Anatomie des Vers intestinaua Ascaride lombricoide ct Echinorynque 
géant. Avec 8 pl. Paris, 1824, 4to. 
A. Von NorpMann, Mikrographische Beitriige zur Naturgeschichte der wirbellosen 
Thiere. Istes Heft. Mit ro Kupfertaf. Berlin, 1832, 4to. 
F. Dusarpin, Histoire naturelle des Helminthes ow vers intestinaux. Avec 12 pl. 
Paris, 1845, 8vo. 
Other important, more special works of MEHLIS, CrePLIN, Lruckart, C. To. Von 
SIEBOLD, will be indicated further forward. See also the article Antozoa of OwEN in 
Tovn’s Cyclopedia 1. pp. t1o—144 (1837). ‘ 
11—2 
