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Show 1894.] NEW GENERA OF EARTHWORMS. 385 rather thin-walled, but have a stout duct leading to the exterior. I could not see the least trace of a diverticulum. It is rare for the members of the family Cryptodrilidae, indeed for any worm belonging to the Megascolicidae, to be without diverticula to the spermatheca. There are here and there a few cases, but these are mostly of worms which have a simple structure and are perhaps rather degenerate in their organization. Examples are furnished by the genera Gordiodrilus and Ocnerodrilus. I know of no large and well-developed genus like Millsonia in which the spermathecae are devoid of diverticula. It may of course be that there are really diverticula, but that they are concealed in the thickness of the muscular walls of the duct of the spermatheca. Millsonia nigra, n. sp. (Fig. 1, p. 381.) D E F . Length 230 mm.; diameter 7 mm. Male pore single. Spermiducal glands open each into a bursa copulatrix. External characters.-This species, judging from the single specimen at m y disposal, is rather smaller than the last. It is also rather different in colour, being of a dark brown thoughout, almost black in parts. The setae, dorsal pores, and prostomium are as in the last species ; the clitellum wTas undeveloped. The most salient external difference, apart from colour, that distinguishes this species from the last is in the orifices of the male organs. The male pore, as stated in the definition of the species, is single and median. It is of some size and occupies an area equal to that which would be occupied by the missing ventral setae of its segment. It is surrounded by a smooth area of skin, doubtless the commencement of the otherwise wanting clitellum. The spermathecal pores are also fairly conspicuous, but they are paired, though the orifices are very close together. These orifices correspond in position to the ventral setae. They are on the boundary line of segments viii./ix., though, as will be pointed out later, the pouches themselves lie principally in the viith segment. Lntersegmental Septa.-The character of the septa plainly distinguishes this species from the last. They commence at the same segment, i. e., between segments iv./v., but they are from the first thickened ; the last of the series of thickened septa separates segments xiii./xiv. Numerous stout muscular strands tie them together and to the parietes. These bands are found also attached to the septa separating segments xiv./xvi. Nephridia.-This species shows the peculiar character of the nephridia better than does the last. On opening the body the nephridia of the anterior segments were seen to present the usual characters of the diffuse nephridia; those of the fourth and fifth segments seemed to be a little thicker than the others, but whether these formed a compact " peptonephridium " I am unable to say. Elsewhere (in the anterior segments) the nephridia were scattered tubules not quite so densely packed as in Millsonia rubens. Further back the coiled masses of tubes seem to disappear and to be |
