Art. VI.—Note on a curious Double Worm.
[Read before the Wellington Philosophical Society, 19th January, 1886.]
Some time ago, Mr. W. Marshall informed my father that there were some curious double worms in the Rangitikei, and promised to send him one. This promise he fulfilled a few weeks ago, the specimen now on the table being the one sent. It was placed in my hands for determination. I am not aware of any record of an Annelid of similar appearance. The anterior portion is about 1 inch in length and ¼th of an inch in diameter, and presents nothing peculiar so far; but from the posterior end of this
thick part, which terminates abruptly, spring two limbs, each 2½ inches in length, and of an average diameter of ⅛th inch. These appendages make the animal look most grotesque. At first sight, these limbs look as though two worms of smaller circumference were grafted on to an abnormally short and thick individual. At times they trail behind like two tails, or are gathered up, sometimes together, sometimes one is moved first, the body pushed slightly forward with that, then the other is used, and so on alternately. The anal aperture is situate immediately at the posterior end of the thick portion, and between these two limbs or tails. There is no aperture in the end of either limb, though there is a spot which at first sight gives the impression that an opening is present.
I have not yet examined it very critically, lest it should sustain damage and die before I was able to exhibit it to this meeting.
It is a species of Acanthodrilis; but the question arises: Is it only an abnormal form, or are they tolerably common? Probably they are far from rare, as Mr. Marshall, in forwarding it, says: “I send you one of those two-tailed bush-worms I spoke to you about;” thus implying that he had seen others. He has been asked to endeavour to procure more specimens, and to send any information in his possession regarding their habits, abundance, etc. Till this information is received I prefer to suspend further decision as to its specific value.
This note was written for a meeting called in October, and which lapsed for want of a quorum. The worm has since died; but, as no other specimens have yet been received, I hesitate to dissect this one, and until that is done I feel that the examination is necessarily incomplete.
Description of Plate VIB.
Fig. a. Double worm (Acanthodrilis), seen from above.
Fig. b. " seen from below.