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Show 1892.] NEW SPECIES OF EARTHWORMS. 143 probably is somite i., and the next two annuli belong to somite ii. (see pi. xv. fig. 1 of m y paper, loc. cit.). The chaetae of both the new species differ from those of the previous species in the presence of an " ornamentation," similar to that of the chaetae in Rhinodrilus1, and consisting of longitudinal rows of obliquely transverse ridges2. The clitellum is evidently not fully developed, but the intersegmental grooves on the dorsal surface of somites xix. to xxviii. are partially obliterated (this area includes the 26th to 35th annuli). Along each side of the body there is a very pronounced latero-ventral ridge extending across somites xvi. to xx., the body being here flattened, though probably the appearance, as represented in the figure (Plate VII. fig. 5, t.p.), is less marked during life. This ridge is glandular and appears to correspond with the structures known as the " tubercula pubertatis " in Lumbricus, Allolobophora, Rhinodrilus, &c. By teasing up the body-wall, and by the examination of sections, I find the clitellar cells to occur over a much wider area than that represented by the above numbers, viz. as far forwards as somite x., so that we may, I think, conclude that the clitellum, when fully developed, covers the somites x. to xxx. This agrees closely with the extent of the same organ in M. rappi as described by Beddard ; in the specimen examined by myself it occupied somites xiv. to xxvi.3 In M. beddardi the clitellum is less extensive, covering somites xi. to xxiii.; but in neither of these species did I find the limits well defined. Although I did not observe, when I was engaged upon the previous species, anything like tubercula pubertatis, yet I figured for M. rappi i the ventral edges of the clitellum as being well marked and thickened ; a re-examination, too, of specimens of M. beddardi reveals, though in a very indistinct manner, owing to their very poor condition, a band along each side of the clitellum, which is no doubt of the same nature. The nephridiopores are, as in the other two species, very distinct even along the clitellum ; they are placed in front of the outer chaetae, i. e. along the sides of the body, the first nephridiopore occurring in somite iii. There are no dorsal pores, nor could I detect any of the generative apertures. But on either side of each of the somites x. and xxiii., that is on the somites which carry the 8th and 21st nephridiopores respectively, occupying the position of the inner chaetae, is a rounded papilla (Plate VII. fig. 5, cp., cp'.), slightly pitted 1 Perrier, " Lomb. terr.," Nouv. Arch. d. Museum, 1872, pi. i. fig. 11; Horst, Notes from Leyden Museum, 1887, pi. i. fig. 7. 2 Mr. Beddard has recently described, in the ' Annals & Mag. Nat. Hist.' Feb. 1892, ornamented chsetae in Anteus, Geoscolex, and Pontoscolex, Schmarda ( JJrochceta, Perrier). 3 As I have remarked in m y " Attempt to Classify Earthworms," we must increase the numbers given in m y description of M. rappi by one, as the apparent first somite is in all probability somite i. and ii., the chtetse of somite ii. having disappeared. 4 Loc. cit. pi. xv. fig. 1. |
