472 Dr. O'Bryen Bellingliam on Irish Entozoa. 



vauce more than one branch of natural history, and who has 

 lately turned his attention to these much-neglected animals, and 

 has described some species altogether new to science. 



Under the general name Entozoa (derived from eWo?, intus, 

 Lfioov, animal) arc included all the animals which naturally and 

 permanently reside in the alimentary canal, or some other part 

 of the interior of annuals. And although the habitat of any ani- 

 mal is not a sufficient ground to separate it from the genera or 

 species which approach it in organization, yet as the Entozoa have 

 been studied and described as a separate group by those natu- 

 ralists whose authority upon the subject is the highest ; and as 

 the majority of them are distinct in organization from any ani- 

 mals not parasitic ; and as we are as yet far from having arrived 

 at a natural arrangement of invertebral animals (there being some 

 groups which, though not parasitic, require to be associated with 

 the Entozoa, and others which are pai'asitic, and which many have 

 arranged with these animals, but of which the true situation is 

 extremely doubtful); — it appeared to me to be more prudent to 

 retain the term in the sense used by Rudolphi and Bremser ; and 

 on the present occasion I shall confine myself altogether to the 

 true Entozoa, or those species which inhabit some part of the in- 

 terior of the bodies of other animals ; and I shall not enter at all 

 upon the disputed point, as to the place which these animals 

 ought to occupy in a natural arrangement of the invertebral 

 kingdom. 



The animals included under the term Entozoa, although they 

 have been very carefully studied by several continental zoologists, 

 and have occupied a considerable share of the attention of several 

 distinguished comparative anatomists, have from some cause or 

 other been little attended to, I might almost say completely over- 

 looked by British naturalists, even by men distinguished in other 

 departments of the science. " ^\1iile there are some branches of 

 natural history (as Mr. Jenyns has observed in his ' Report on 

 Zoology ') which are most sedulously cultivated by us, there are 

 others which have for a long time lain comparatively neglected.^' 

 This remark is peculiarly appropriate, and applies particidarly to 

 the animals which form the subject of the present communication ; 

 they are commonly looked upon wdth disgust instead of anything 

 of interest in a scientific point of view, and the number of indi- 

 viduals who have made them a study is exceedingly limited. In- 

 deed, the little attention which the Entozoa have attracted in 

 these countries will be apparent from the fact, that in the only 

 works which contain lists of the British species, viz. Pennant's 

 'Zoology^ andTurton's 'British Fauna,' but twenty-eight species 

 are described as indigenous ; and four of these are repeated twice 

 under different names, leaving but twenty-four distinct species : 



