DESCRIPTIONS OF GENERA AND SPECIES 477 



spermiducal glands of the seventeenth segment, there are two pairs of tubular 

 glands^ — a pair to each segment — of the same character, though rather smaller. 

 MiCHAELSEN (10) has, however, referred two earthworms from tropical Africa to the 

 same genus, which do not show this peculiarity, though agreeing in most other 

 matters with my Dichogaster damonis; by neglecting this character, and also the 

 absence of the ventral setae upon segments xvii, xviii, xix, which both distinguish 

 B. damonis, the genus Dichogaster is reduced to a condition in which it is very 

 difficult to define it. The above definition, however, does exclude the genera 

 Gryptodrilus, Megascolides, and JDigaster, in a few coniparatively triffing points ; 

 thus, in all of those genera the male pores are upon the eighteenth instead of 

 the seventeenth segment. These differences cannot be looked upon as important ; 

 but then, hardly any of the points in which many of the genera of Cryptodi-ilidae 

 differ are important ; and it is necessary to divide so large a family into genera ; 

 I am not sure that it would not be advisable to retain the name Dichogaster for 

 my species only, and to apply a new name to Michaelsen's species, which show the 

 differences referred to, and are, moreover, peculiar to the Ethiopian region. It may 

 be noted also that there is nothing in Michaelsen's description, which is opposed to 

 uniting with his two species of ' Dichogaster ' my genus Microdrilus (q. v.). With these 

 preliminary remarks I leave for the present the genus as Michaelsen has wished, 



(i) Dichogaster damonis, Beddabd. 

 D. damonis, Beddabd, Q. J. M. S., vol. xxix, 1889, p. 351. 



Definition. Length, about 4 inches. Clitetlum, XIII-XX. Ventral setae of XVII-XIX 

 missing ; three pairs of tubular glands open on to these segments, of which the anterior is 

 connected with sperm-duct. A pair of peptonephridia open into buccal cavity. Hab. — Fiji. 

 In this species the calciferous glands are in the fifteenth, sixteenth, and seven- 

 teenth segments. The single pair of spermathecae have a single diverticulum; this 

 has very thick walls, and its cavity is much subdivided. I have illustrated the 

 anatomy of this species in my memoir quoted above. 



(a) Dichogaster mimus, Michaelsen. 



D. mimus, MiCHAELSEN, Arch. f. Nat., 1891, p. 203. 



Definition. Length, 40 mm. ; number of segments, 350. CUtellum, XIII-XXIII. No penial 

 setae. Hab. — Accra, West Africa. 



