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Show 1870.] DR. T. S. COBBOLD ON A NEW ENTOZOON. 11 fected embryos, present an average length of 7-5-jj" by -g-gV' m width but the fully developed embryos, when set free and unrolled, give an average measurement of y^-g*" from head to tail. The larvae, however, are remarkably thin, the longest of them not exceeding the -^-fayj" in thickness ; yet, notwithstanding their smallness, they have already attained the general form of their parents, the finely pointed anterior extremity of the body scarcely exceeding the * •" in diameter. In this connexion, I must also not omit to mention that on removing the batch of parent worms from the phial in which they were sent, I observed several of them to be adhering to one another, the various points of union being marked by the presence of minute particles of debris. To the naked eye these particles presented a pale yellow colour, their irregular outline and general aspect suggesting that they were only patches of mucus, connective tissue, or something of that sort derived from the " host " during dissection. However, to m y astonishment, on microscopically examining one of these little masses, measuring about the fa" in length, I found it to consist of thousands of embryos agglutinated together. So consolidated had they become by the action of the spirit in which they were preserved, that I had the greatest difficulty in isolating any one of them; and since, also, they were, individually, much shrivelled and twisted, their measurements could not be very accurately taken. Making all due allowance for contractions and alterations of shape, I did not find that their separate total lengths perceptibly exceeded that of the embryos obtained from the interior of the parent worms. In the mass they were coiled upon themselves and each other in inextricable confusion. I purposely dwell upon these apparently trivial matters because it seems to m e of the highest importance to ascertain whether the escaped embryos were, or were not, caught in the act of migrating. They may have accumulated only as the result of accidental evacuation from specimens of the parent worms injured during the dissection of the "host;" in this case, however, though the egg-envelopes would naturally have disappeared, I should probably have noticed some of the freed embryos in a less perfectly developed condition than that in which all of them actually appeared to be. Those who are acquainted with the migratory habits of the Nematode Entozoa will readily conclude that these embryos were, at the time of the "host's" death, accomplishing what, in other cases, has been appropriately termed a " first active wandering " on their own account; and probably a passive transference to some unknown intermediary bearer would, had they lived, have been essential to the further development of these particular larvse. Be that as it may, in the matter of ascertaining their mode of actual escape (supposing them to have obtained their freedom naturally) there yet remains the rather awkward circumstance that I have not yet succeeded in procuring evidence of the existence of any reproductive outlet in the body of the parent worm. In establishing a new genus for the reception of this interesting-form of Entozoon, some explanation is certainly necessary. At once, therefore, I may remark that I should have preferred to designate |
