672 OLIGOCHAETA 



of the organ ; afterwards this caecum becomes very much less pronounced. The 

 testes are two pairs in x, xi ; each is concealed within a backward prolongation of 

 the median sperm-reservoir (see PI. iii) ; with the sperm-reservoir of each segment 

 is connected a pair of sperm-sacs which depend respective^ into the eleventh 

 and twelfth segments. The ovary, as I have pointed out, is a body, not identified 

 by Benham, in the thirteenth segment; the structures which both Benham and 

 I mistook for ovaries are really egg-sacs which occupy the usual segment, i. e. the 

 fourteenth. The spermathecae are in segments xiii-xvi, inclusive ; there are not more 

 than eight in any one segment and usually fewer. 



(2) Microcliaeta beddardi, Benham. 

 M. Beddardi, Benham, Q. J. M. S., vol. xxvii, 1887, p. 78. 



Definition. Length, 370 mm. {about) ; nmnher of segments, 365. Clitellum, XI— XXIII. 



Calciferous gland in IX, X. Testes, one pair, Spermathecae ^, one pair in each of 



segments XII and XIII. Hab. — Natal. 

 This species of Microchaeta agrees with the last in most characters ; it has the 

 same commencing ' cephalization ' — i. e. the second segment as well as the first has 

 no setae, and the two segments are fused. Segments iv-vii are bi-annulate, but the 

 rest are simple. In the alimentary canal the shape of the calciferous gland distinguishes 

 the two species ; in the present the gland appears to be single as in the last, but it 

 is nipped at its centre by the septum dividing segments ix/x, and therefore lies 

 partially in both of these segments. The doubling of the dorsal vessel is limited to 

 segments vii-ix. 



(3) Microcliaeta papillata, Benham. 



M. papillata, Benham, P. Z. S., 189a, p. 141. 

 Definition. Length, 250 mm. Calciferous gland, in X. Testes, two pairs. Spermathecae, 

 five or six pairs in each of segments XIII, XIV. Gopulatory setae, and glands in 

 X and XXriI. Hal.- Natal. 



This species comes nearer to M. rappi than to M. beddardi; it agrees with the 

 former in the doubling of the dorsal vessel and in the number of hearts, as well as 



' The spermathecae are stated by Benham in his original description of this species to be four in 

 number, a pair to each of segments xii, xiii ; in one case there was a variation, an additional spermatheca 

 being present on one side of the body in one segment ; this arrangement is figured. 



