Pers Le NP CE OI TS TS PT TV Tee weh Sag te CP > 
ON THE ANGUILLULIDE. 75 
rewarded by the most gratifying results—more especially as, with the exception of the 
“Paste” and “ Vinegar Eels,” the Vibrio tritici, and one or two unknown species always 
alluded to by the same name of Anguillula fluviatilis, no representatives of this group 
have, I believe, yet been described as existing in Great Britain: hitherto the harvest 
has been with the continental naturalists, with Dr. Leidy in America, and with our own 
countryman Carter in India. 
As a result of my investigations, I am inclined to believe that these free Nematodes 
will be found to constitute one of the most widely diffused and numerically abundant 
groups in the whole animal kingdom, rivalling, in the first respect at least, the almost 
ubiquitous Diatomaceæ. A statement of some of the principal situations in which I have 
met with these animals will best illustrate this proposition. "Thus, beginning with the 
land- and freshwater-species, I have found them in all the specimens of soil examined, in 
moss, yarious species of lichen, about the roots of fungi', also the roots of grasses, and 
between the sheaths of their leaves, amongst the mud of ponds and rivers, on the fresh- 
water Algæ, amidst decaying liverworts and mosses, and on submerged aquatic plants. 
The marine species exist in great abundance in the surface-mud of rivers and estuaries’, 
in the sand, and amongst the small stony débris under the shelter of rocks, as well as in 
the tide-pools, where they swarm about the roots of the corallines and on some of the 
smaller and finer sea-weeds, especially those having a dingy appearance from the pre- 
sence of Diatomaceæ. And, lastly, two or three species I have found in the greatest 
abundance, as pseudo-parasites, within the substance of some of the softer sponges. So 
numerous are they in these latter situations, that it is rather surprising they should have 
so long escaped the attention of marine zoologists. From the transparency of their in- 
teguments, they are not only beautiful microscopical objects, but also admirably adapted 
for anatomical research ; and Dr. Eberth and myself have already worked out so many 
interesting structural details, that I have no doubt, should the investigation be followed 
up by other observers, the question of the anatomy and real affinities of the Nematoids, 
at present so doubtful, would be soon placed upon a satisfactory footing. 
The specimens I have examined have varied in length from 75” to nearly 2^, almost all 
the larger forms being marine, though Dorylaimus stagnalis, Dujard., is about 3° long, 
and far exceeds in size any of the other land or freshwater species I have met with. In 
their various habitats individuals of all ages may be seen, from the young, immature and 
non-sexual embryo just emerged from the egg or its parent, up to the adult condition; 
ee the ova of species infesting a particular sea-weed may be seen attached 
This k t the parent worms are gliding and twining, serpent-like, amongst its branches. 
alone would induce one to believe that these animals are never parasites at any 
mo of their existence, even if this view were not confirmed by the existence of ana- 
peculiarities which seem to distinguish them as a group from the parasitie forms 
! > 
att? et been very successful in finding these animals on or in fungi, though Carter has discovered them in 
trunk of a oo ias from the conceptacles of a large species of the genus Xylaria, growing on the decayed 
* Lhave found six a (Trans. of Med. and Phys. Soc. of Bombay, 1861, App. p. 1.) 
9n à shilling piece. ierent species existing, more or less abundantly, in a small portion of mud that could be held 
L 2 
