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Show 234 MB. F. E. BEDDAED ON NEW EAETHWOBMS. [Mar. 19, species of Microscolex and Acanthodrilus agree in that the sperm-sacs are in xi. or in ix. and xi.; this is not a usual position. With this may be compared the fact that the Australian Cryptodrilids frequently agree with tbe Australian Perichaetas in that the sperm-sacs are in segments ix., xii., also not a usual position. (5) Microscolex gracilis, n. sp. This species might easily be confounded with Microscolex diversicolor, at least with the less strikingly-coloured examples of that species. It has precisely the same dark purple colour dorsally, the implantation of the setae being yellowish white; the end of the body, too, has the quadrangular aspect of the corresponding part of the body in Microscolex diversicolor. It is, however, in spite of this superficial likeness, quite a different species. There were three examples, of which the largest measured 72 mm.; the diameter was 2 mm., except at the clitellum, where it was 3 m m . This individual consisted of 88 segments. It is therefore a long and slender worm ; the clitellum is very prominent. It may be at once differentiated from Microscolex diversicolor by the fact that the prostomium is not continued by furrows over the whole of the buccal segment. The setae are more or less distant, being divided by equal distances at the posterior end of the body, where the middle line of the segments is ridged. The setae are here particularly large. The clitellum occupies segments xiii.-xvi. and is complete. I could not see any dorsal pores. The male pores are separated by moderately wide intervals from each other; the orifice is wide anil suriounded by a crenate margin. The first septum separates segments iv./v. Septa ix./xii. are thickened. The gizzard is well developed; it lies in segment viii. The nephridia begin in segment ii. ; they end in a muscular sac. The sperm-sacs are in xi., xii. In a specimen investigated by longitudinal sections they occupied segment xi. only. The testes and sperm-duct funnels lie in x. The spermiducal glands are stout and massive ; they have a slightly sinuous course and occupy three segments. The penial setae are also stout aud not particularly long. They are bent like a bow, slightly expanded at the free end, but not ornamented. The muscular duct, when traced back into the glandular part of the spermiducal gland, is seen to stop abruptly ; its lining epithelium suddenly ending and being replaced by the indistinct lining epithelium of the glandular part of the organ. Followed iu the other direction, the duct winds about and receives the sperm-duct a considerable distance in front of its external orifice ; the latter opens at the end of a papilla, which projects into the interior of the gland-duct, which is at this point widened: it is suggestive of the penis of the Tubificidae, &c. Further down the duct receives the |