126 H. CHARLTON BASTIAN ON THE STRUCTURE AND 
without through the skin of fishes and of frogs, into the bodies of snails, and in large 
numbers into the eyes of freshwater fishes, as discovered by Nordmann*. 
Should this supposition of Mr. Carter prove correct, as the very close correspondence be- 
tween the anatomy of these microscopic Filaridee and of the Guineaworm renders highly 
probable, several very interesting questions arise for solution. Did the young worm seek 
its new habitat before or after impregnation? Why are females only discovered in the 
body ? And is there one species of Dracunculus only, or many, corresponding with different 
species of microscopic Filaride ? 
Mr. Carter thinks it probable that these worms enter the body whilst very young, and 
when they are not more than 44'5;5th of an inch in diameter, and at this early period of 
their existence they have only the rudiments of genital organs; so that he thinks they 
must be unimpregnated when they penetrate the integuments. And seeing that a full-sized 
Guineaworm measuring eight or ten feet in length is, as it were, a continuous sae fully dis- 
tended with the very minute young, it must contain a progeny numbering at least two or 
three millions, and Ithink it would be difficult to understand how a young worm, containing 
this number of ova, could be so minute as entirely to escape observation whilst pene- 
trating the skin; it would also be very diffieult to conceive how the female of so 
minute an animal could receive a sufficient quantity of the male fluid to fertilize such an 
enormous quantity of ova. 
It does not seem at all probable, either, that in its new situation beneath the integu- 
ments the female could be brought into contact with a male; and therefore when 
Mr. Carter suggests that the young may have been produced from * buds "f instead of 
fertilized ova, I think he has suggested the real- explanation of their genesis, and that I 
shall be able to support this position by several pretty conclusive arguments. 
Much light has of late been thrown upon this process of “ parthenogenesis ” by the 
able investigations of Mr. Lubbock i and Professor Huxley§ ; and we need have the less 
hesitation to call in the aid of so exceptional a process to explain the history of the 
Guineaworm, seeing that this method of reproduction has been recognized in so many 
animals much higher in the scale of organization, as may be seen from the following valu- 
able résumé, by Professor Huxley, of the classes and orders in which it has been met with. 
He says, * Among the Annulosa, the Rotifera and Turbellaria possibly possess it to a small 
extent; the Nematoidea|| do not possess it at all. Many Trematoda possess it ; others, 
such as Aspidogaster, have nothing of the kind. The Acanthocephala are not known to 
possess it; the Echinodermata are regarded by Professor Owen as possessing it, but their 
different families show every gradation from simple metamorphosis to something like 
agamogenesis. A few Annelida possess this power in a marked degree ; in many, nothing 
of the kind is known. The Nais has it; the Earthworm and the Leech have it not. 
Of the Crustacea, some, such as many Branchiopoda, exhibit it in the highest perfection ; 
* Steenstrup's * Alternation of Generations,’ Ray Soc. edition, translated by Busk, p. 98. 
T Aun. of Nat. Hist., 1859, vol. iv. p. 109. 
t “On Two Methods of Reproduction in Daphnia,” Phil. Trans., 1857 and 1859. 
$ “On the Agamic Reproduction and Morphology of Aphis,” Trans. Linn. Soe., 1858, vol. xxii. 
|| Of course, if subsequent investigation confirms the opinion here adopted, this statement would require alteration. 
