288 W. B. BENHAM. 



YiG. 4. — Didymogaster. a. Genital system. The clitel- 

 lum, XIV to XVIII. SF.^, sp.^^ are the first and third sperraa- 

 thecae. s. The digitate sperm-sac of Somite ix. ps. The sac 

 of penial setae; and pro.^ the prostate, b. Alimentary system. 

 G.^, G.2 The two gizzards lying in Somites vi and vii. Both 

 diagrams modified from Fletcher's figures of D. sylvaticus 

 in ' Proc. Linn. Soc. N.S.W./ i (2nd ser.), 1886. c. repre- 

 sents three somites from any part of the body, and shows the 

 arrangement of the setse ; the nephridiopores are probably, as 

 in other plectonephric genera, numerous. 



Distribution : Australia. 



Fig. 5. — Perissogaster. a. Genital system. ps. Sac 

 with penial setae, pro. The unequally lobed prostate. b. 

 Alimentary system. g.\ g.^^ g.^ The three gizzards, d. The 

 first dilatation of the intestine in Somite ix, followed by five 

 others, all of which are doubtfully calciferous. s. The com- 

 mencement of the sacculated intestine in Somite xv. c. shows 

 the arrangement of the setae. Constructed from the descrip- 

 tion given by Fletcher for P. excavatus in ' Proc. Linn. 

 Soc. N.S.W.,' vol. ii, ser. 2, 1887. 



Distribution : Australia. 



Fig. 6. — Dichogaster. a. Genital system, pro.^ The 

 first prostate, communicating with the sperm-duct, pro." and 

 PRO.^ The second and third prostates, which are independent 

 of the sperm-duct. b. Alimentary system, c.^, c.^ The two 

 gizzards, each occupying two somites. Ca. The first of the 

 three calciferous diverticula on each side. s. The commence- 

 ment of the sacculated intestine, ipn. The intra-buccal pepto- 

 nephridium with its duct. c. represents the Somites xvi, 

 XVII, and xviii externally. The large black dots in xvii are 

 the male pores, those in xviii the prostate pores of this somite. 

 In these two and in Somite xix the inner couples of setae are 

 absent. Modified from the figures given by Beddard for D. 

 damonis in ' Quart. Journ. Micr. Sci.,' xxix, pis. xxiii, xxiv. 

 Distribution : Fiji. 



