. The Annals and magazine of natural history; zoology, botany, and geology. Natural history; Zoology; Botany; Geology. 94 Mr. F. E. Beddard on the spermathecge which open on to the exterior in the following segment (the 13th). I am inclined to regard the diver- ticulum in question as the equivalent of the second vas deferens of the Lumbriculidae ; and it may also furnish a clue to the origin of spermathecae. It seems a reasonable hypo- thesis to derive these organs from diverticula of the genital ducts. At present, however, both these suggestions are put forward only tentatively. This genus ca
. The Annals and magazine of natural history; zoology, botany, and geology. Natural history; Zoology; Botany; Geology. 94 Mr. F. E. Beddard on the spermathecge which open on to the exterior in the following segment (the 13th). I am inclined to regard the diver- ticulum in question as the equivalent of the second vas deferens of the Lumbriculidae ; and it may also furnish a clue to the origin of spermathecae. It seems a reasonable hypo- thesis to derive these organs from diverticula of the genital ducts. At present, however, both these suggestions are put forward only tentatively. This genus can be recognized as a perfectly distinct form by an examination of its external characters only, which is by no means always the case with the Oligochseta. The seta? are highly characteristic, and their shape can be best appreciated by an inspec- tion of the accompanying Fig- 2. woodcut (fig. 2). The dorsal rows consist each of a single capilliform seta, not unlike those of the Tubificidse (cf. e. g. Antonin Stole " Mono- graphic Ceskych Tubificidu, Morfologicka a Systematika Studie," Abhandl. bohni. Ges. Bd. vii. 1888, Taf. iv. fig. 13 «1) ; in some of the an- terior segments only was there occasionally a second seta, but of the same form. The ven- tral rows are made up of a series of paired setas — one pair in each row. The two seta? of each pair are not quite alike in form, and one is markedly larger than the other. This can hardly be due to a difference in age, as every segment corresponded. These seta3 are not quite similar to those of any other genus of Oligoclneta. Their extremities are not bifid. 1 am disposed to regard this genus as the type of a new family lying between the Lumbriculidse and the Naido- morpha, though its affinities to both are only very general j but our knowledge of the aquatic. Setse of Phreodrilus. a, dorsal seta ; b, c, ventral Please note that these images are extracted from scanned page images that may have been digitally enh
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