Lanicides vayssierei (Gravier 1911)

“TEREBELLA VAYSSIERI Gravier.

Phyzelia vayssieri Gravier (1911), p. 130, pl. X, figs. 121-123; pl. XI, figs 134, 135.

The tube of this species, of which several were gathered, consists of variously coloured sand grains, loosely and irregularly arranged to form a thick wall not unlike that of some tubes of T. ehlersi.

The worms attain a length of 40 mm., with a diameter of 6 mm. anteriorly, at about the 8th segment ; the body begins to contract at about the 15th segment to 4 mm., which diameter is retained for some distance, and then it begins to taper.

There is one point upon which I lay stress in identifying the worm, and that is the form of the uncinus in the anterior segments ; the great length of the basal process, which starts below the teeth of the uncinus, seems to be characteristic,

There are indeed one or two points in which my specimens seem to differ from Gravier's account, which may be due to differences in the state of preservation or of age. Thus, he states that he could detect no eyes. In most of the present worms these are distinctly present as a series of minute black dots, in two to four rows on each side : this oculiferous area occupies about half the height of the prostomium on each side. In some of my specimens, however, they are absent. And it has been noted by Ehlers and other authors that in some species of Terebellids eyespots are sometimes present, sometimes absent.

I think that Gravier must have overlooked the fact that the ventral surface of 2nd and 3rd segments coalesce, though they are distinct laterally and dorsally, and laterally the 2nd segment is very much compressed, and therefore quite short. He states that the “flap” is borne by the 2nd segment. I find it distinctly on the next. Also the first gill is said to be on the first segment, instead of, as I find it, on the 2nd.

Again, Gravier writes that "there is only one row of uncini." This is true for the anterior and posterior segments, but from about the 10th to the end of the thorax, that is to segment 18, I find that there are two series of uncini close together and facing alternately fore and aft, interdigitating with each other, so that they simulate a single row till examined under a microscope.

The bristles of the 1st notopod have simple points, with a narrow flange on both sides, which is not striated. But the bristles of the later segments are stouter, with a narrow flange on one side and a broader one on the other, each faintly striated.

Apart from these slight discrepancies I think there is no doubt that the worms before me are identical with those described by my French colleague.

Locality .—

Boat Harbour, 3 ½ –4 fathoms.

Distribution .—Off Terre Alexandre and Port Cironcision (île Petermann).

Remarks .—Both Ehlers and Gravier, in discussing the allied form T. (Phyzelia)

fasciata Grube, show how difficult it is to define the genera and sub-genera of this family; they give up in despair the attempt to set things right for these exotic species, although De St. Joseph has arrived at some apparently satisfactory conclusions with regard to the European species.

In dealing with this species Gravier expresses himself as being unable to decide whether it should come into the genus Polymnia Mlmgrn, or Nicolea or Scione, and yet finally he places it in Phyzelia, which has received different limitations by various authors. Under the circumstances it may be as well left in the genus Terebella lato sense.”

(Benham, 1921)