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II. Monograph on the Anguillulide, or Free Nematoids, Marine, Land, and Fresh- 
water; with Descriptions of 100 New Species. By H. Cuaruron Bastian, M.A., 
MB. Lond., F.L.S. 
(Plates IX.-XTIT.) 
Read December 1st, 1864. ; 
OF the Helminths hitherto described, those belonging to the Nematode group far ex- 
ceed in number of species the representatives of either the Trematode or the Cestode 
orders, and, as far as our present knowledge extends, they have also a wider distribution 
as parasites amongst the various members of the animal, kingdom. Thus, commencing 
with the Acalephe, we find the so-called Nematoideum Cydippes taking up its residence 
in the substance of the body of one of our smaller jelly-fish, and thence onwards through 
higher and diverse types of animal life they are found, in more or less plurality, infesting 
representatives of all the principal orders and classes, till we come to man himself, who 
is the. chosen habitat of no less than twelve species. Happily, however, whilst thus 
numerous and widely diffused, their effects are less pernicious and more seldom fatal 
than those resulting from the presence of individuals of the Trematode or Cestode types 
in their various stages of development. 
As regards the actual number of parasitic Nematoids at present known, it has bee 
computed by Dr. Cobbold, in his recent work on * Entozoa,' that these do not amount to 
more than about 550 distinct species; and when I mention that within a space of fifteen 
months I have obtained from a few limited regions no less than 100 new species of free 
Nematoids, some idea may be formed of the numerical importance of this last ‘group, 
concerning which, till within quite a recent period, our knowledge has been so vague 
and unsatisfactory. 
Borellus?, more than two centuries ago, seems to have been the first to recognize and 
describes member of this family ; and we must look, therefore, upon the so-called ** Vinegar 
Eel,” whose discovery he announced, as the first known representative of this group of 
prias Nematoids to which I refer. The same animal was subsequently seen by 
ower, Hooke, Leeuwenhoek, Baker, Spallanzani, and other pioneers of microscopical 
co. soon found a companion for it in its near ally, the “ Paste Eel.” Then came 
very by Needham °, in 1743, of the wonderful Vibrio tritici and its young so 
Strangely tenacious of life ; and afterwards Otto Müller‘ was followed in his recognition of 
^ exceptions to this general rule, three Nematoids may be cited which are undoubtedly most serious pests to the 
: es zn frequency of their occurrence and the serious diseases to which they give rise: these are the 
Fe: Stegen 18 so prevalent in the tropical parts of Asia and Africa; Sclerostomum duodenal; principally 
or less from « t, and 80 common that Dr. Griesinger considers about one-fourth of the whole population maler: more 
Situation AL. chlorosis” (a malady that is frequently fatal), due to the presence of these parasites in the 
to the : y za name; and, lastly, Trichina spiralis, which has attracted so much attention of late, owmg 
of trichinosis, in various parts of Germany more especially. 
1 e 
Obs. micr 
VOL, xxy : Centur. 7, 1656, * Micr. 99, tab. v. 7. * Animal. Infusoria. 4to. Hamb. 1786. 
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