OCR Text |
Show 1891.] EARTHWORM FROM WEST AFRICA. 49 in length, with a diameter at the widest part of about } inch. As the specimens were much softened, this length probably represents the extreme length of the worm in its most extended condition. The colour was almost black at the anterior end ; further back a brown tint predominated ; the posterior end of the body showed in many specimens a peculiar dark green colour, something like that of Microehceta rappii1. The appendages in question are as shown in the accompanying drawings (woodcuts, figs. 1, 2), small, not longer Siphonogaster millsoni. Ventral view of anterior segments, showing the processes of segment xviii. than two segments ; they are directed backwards and appear sometimes as if they were adherent along their whole length to the ventral parietes. In other specimens they hang freely down. Levinsen is in some little doubt about the number of the segment to which the appendages are attached. In S. millsoni they arise without doubt from the eighteenth segment, close to each other and on either side of the ventral middle line. Their origin is from the middle of the antero-posterior diameter of the segment, just where the ventral pair of setse would be placed were they developed upon this segment. They correspond, in fact, exactly to the first seta, as may be seen by an inspection of the ventral surface of the worm mounted in glycerine on a slide. The setce of this species, it should be remarked, are in couples, the distance between the individual setse of each couple being considerable- greater in the case of the ventral couple. 1 Beddard, " On the Anatomy and Systematic Position of a Gigantic Earthworm, &c," Trans. Zool. Soc. vol. xii. p. 63, pi. xiv. PROC. ZOOL. Soc-189i, No. IV. 4 |