OCR Text |
Show 50 MR. F. E. BEDDARD ON AN [Jan. 20, On the eighteenth segment, as already mentioned, the ventral couples are absent, but the dorsal couples are present. The shape of the setae is very characteristic and is correctly given by Levinsen (loc. cit. pi. vii. fig. 6). I could observe no differences, except with regard to size, on any part of the body. Their colour is, however, somewhat remarkable. The setae of Earthworms are generally of a "horn-yellow" colour. In this species the colour appears to be much the same ; but when a seta is viewed with the light passing from below through its entire length it appears distinctly red. The appendages of the eighteenth segment are of an oval form (fig. 2, a, b), with a narrow neck connecting them with the body- Fig. 2. Appendages of Siphonogaster millsoni. a, ventral view; b, lateral view of segments xvii-xx, showing the processes of the body-wall A ; S, setas. wall; there was no trace of any infolding of the margins such as Levinsen figures. Each appendage is furnished, as in S. cegyptiacus, with a number of peculiar setae, the shape and arrangement of which is rather different from that which characterizes S. cegyptiacus. In that species there are three or four irregular series of the setae, beginning at about the end of the first third of the appendage and reaching to its very extremity. In S. millsoni the setae are disposed in two parallel lines, each of which is near the lateral margin of the appendage ; they lie upon the posterior surface of the appendage. The setae themselves are shaped, as in £. cegyptiacus, like a spearhead with a very short shaft; but in S. millsoni, as shown in the accompanying drawing (fig. 3, p. 51), which may be compared |