| OCR Text |
Show 1889.] OLIGOCHiETOUS FAUNA OF NEW ZEALAND. 379 Dorsal blood-vessel completely double. Alimentary tract. The gizzard occupies segments vi. & vii. Calciferous glands appear as a dilatation of the walls of the oesophagus in segments xiv. & xv. Lntersegmental septa dividing segments vii.-xii. specially thickened. Seminal sacs in segments ix., x., xi., xii. ; those of the last two segments are racemose in appearance. Nephridia diffuse, with numerous external pores. Spermatheca furnished with a variable number of small diverticula. 6. ACANTHODRILUS ROS,E, n. sp. Prostomium completely dividing the buccal segment. Setce strictly paired, the pairs, at least in the posterior region of the body, being equidistant. Clitellum extending over segments xiv.-xix. Dorsal pores present in the posterior segments of body. Dorsal blood-vessel double, but the two tubes unite at the point where they perforate the septa. Lntersegmental septa not specially thickened in the anterior segments. Nephridia one pair to each segment, alternating in position, sometimes opening by dorsal, sometimes by ventral pair of setse. Spermathecce with a long muscular diverticulum, bearing at its extremity a cluster of small pouches. Genus DEINODRILUS, F. E. B. Deinodrilus, F. E. Beddard, Quart. Journ. Micr. Sci. vol. xxix. p. 105. Earthworms with 12 setse in each segment, arranged at approximately equidistant intervals. Prostomium not completely dividing buccal lobe. Clitellum occupies 3 segments (xiv.-xvi.) as in Pericheeta. Nephridia diffuse, opening on to exterior by numerous pores in each segment. Reproductive organs as in Acanthodrilus, i. e. two pairs of tubular atria opening on to segments xvii. and xix. Vasa deferentia open on segment xviii. Dorsal blood-vessel completely doable. 7. DEINODRILUS BENHAMI, F. E. B. Deinodrilus benhami, F. E. Beddard, Quart. Journ. Micr. Sci. vol. xxix. p. 105. Genus PERICHEETA, Schmarda. Pericheeta, Schmarda, Neue wirbellose Thiere, Bd. ii. p. 13. Megascolex, Horst, Notes from Leyd. Mus. vol. v. p. 182. Pericheeta, Perrier, Nouv. Arch. Mus. t. viii. p. 96. As the arrangement of the species of this very large genus is undergoing revision, I abstain from attempting a generic definition. The species described below perhaps merits generic separation, as it differs from most other species in such important points as the possession of tubular atria and paired nephridia. |
