1901.] AND ARRANGEMENT OF EARTHWORMS. 205 



fact that in T. incommodus tbere are the two pairs of sperm- sacs 

 of many Megasodex and Megascolides in segments ix. and xii., 

 which Dr. Michaelsen has thought to be the primitive arrangement 

 of those sacs amoug earthworms. That species also combines with 

 this divergence in structure a peculiar disposition of the sperma- 

 thecal diverticula, which are not arranged in a pair of trifid or 

 mulfcifid appendages as in other species, but in a continuous circle 

 of sacs round the spermatheca. We may perhaps regard this 

 form as the starting point of the genus, the other conditions being 

 arrived at by a loss of one pair of sperm-sacs and a reduction 

 of the spermathecal appendages. It is to be remarked that in 

 other species the sole remaining pair of sperm -sacs has increased 

 in size, which may be connected perhaps with the disappearance of 

 the anterior pair. 



The following is a complete definition of the 



Genus TYPHOEUS Beddard. 



Small to moderate-sized earthworms, with 8 setae per segment 

 arranged in couples. Prostomium large. Clitellum occupying 

 segments xiii.-xvii., partly or entirely. Male pores A'ery con- 

 spicuous and upon segment xvii., corresponding in position to 

 ventral setse. Spermathecal pores upon the interval vii./viii. 

 Genital papillae one to six pairs upon clitellar and neighbouring 

 segments ; rarely absent (?). Dorsal pores present. Gizzard 

 single in viii. ; one pair of ealciferous glands in xii. Intestine 

 furnished with six pairs of glands beginning at about segment 

 Ixxx. Excretory organs micronephi'idia. Dorsal vessel single. 

 A single pair of testes, funnels, sperm-ducts, and (except in 

 T. incommodus) sperm-sacs. Spermiducal glands tubular, with 

 penial setse. Spermathecae one pair with one or two diverticula, 

 or more. 



Hab. India, Ceylon, Burmah. 



The seven species may be thus briefly characterized : — 



Typhoeus orientalis. 



T. orientcdis Beddard, Ann. Nat. Hist. (5) xii. p. 219. 



Length about 100 mm. Genital papillae between segments 

 xiii./xvii, and xviii./xx. in line with ventral setae. Spermathecal 

 pores corresponding to ventral setae. Spermathecae with two small 

 and trifid diverticula. Penial setae with chevron-shaped striae at 

 free end. 



Hab. Neighbourhood of Calcutta. 



Typhoeiis gammii. 



T. gammii Beddard, Quart. Journ. Micr. Sci. xxix. p. 111. 

 Length 250 mm. Genital papillae single and elongated between 

 xix./xx., xx./xxi. Setae paired ventrally, farther apart in lateral 



