468 OLIGOCHAETA 



Genus Pontodrilus, Pebeiek. 



Syn. Lumbrieus, Gkube (in part.). 



Pontoscolex, SoHMAEDA (in part.). 

 Cryptodrilus, RoSA (in part.). 

 Photodrilus, GlAED. 



DEPiuiTioiir. Slender worms witli eight setae per segment, in pairs, the setae of 

 the dorsal pair being usually further apart than those of the ventral. No dorsal 

 pores. Clitellum complete, XIII -XVII. Male pores XVIII. Spermiducal gland 

 tubular, vasa deferentia opening at junction of glandular and muscular parts. 

 Wo penial setae. Spermathecae in VIII, IX, with single diverticulum. Gizzard 

 absent or rudimentary ; no calciferous glands. Nephridia commence in segment 

 XIII or XV. No subnervian blood-vessel. 



The principal parts in the structure of this genus have been treated of in con- 

 sidering the characters of the family to which it belongs. Its anatomy was described 

 in great detail by Peeeiee (9) ten years ago ; since that time I have pointed out 

 that certain structures considered by Peeeier to be of doubtful import, are the testes, 

 and that the gizzard is not entirely absent, as he thought, though undoubtedly very 

 rudimentaiy. I have already given reasons for uniting Giaed's Photodrilus with 

 Pontodrilus ; one other species should, I think, be extracted from the heterogeneous 

 assemblage of forms described under the name of ' Cryptodrilus ' and added to 

 Pontodrilus. 



The genus Pontodrilus, as I define it here, yill therefore contain the five following 

 species : — 



(i) P. littoralis. European coasts. 



(2) P. bermudensis. Brazil ; Bermudas ; Jamaica. 



(3) P. hesperidum. Jamaica. 



(4) P. insularis. Aru Islands. 



(5) P. phosphorous. North France. 



The latter species is placed by Rosa in the genus Cryptodrilus, but not in 

 a decided fashion ; he remarks that it is only provisionally so placed, pending 

 a revision of the family Cryptodrilidae. The reasons which lead me to place it in 

 the present genus are, in the first place, the fact that the nephridia do not commence 

 until the thirteenth segment — a character which is only met with in the genus 

 Pontodrilus (among the Cryptodrilids) ; the gizzard, too, is absent, and there are no 

 calciferous glands. These latter characters, as well as a few others, are not distinctive 



