Akticle XI. — Notes on Species of North American Oligoehceta. 

 IV. On a New Lumbriculid Genus from Florida, with 

 Additional Notes on the Nephridial and Circulatory Sys- 

 tems of Mesoporodrilus asymmetricus Smith. By Frank 

 Smith. 



Premnodrilus palustris n. g. et n. sp. 



The worms here described were found by Mr. Adolph 

 Hempel in a decayed stump in a marsh in Polk county, 

 Florida, in March, 1897. The collection consists of eight 

 sexually mature individuals and a few others that are 

 imperfect or immature. The worms were killed in corrosive 

 sublimate and preserved in alcohol, and are in excellent 

 condition for study. x\ll of the facts pertaining to this 

 species which are presented in this paper have necessarily 

 been obtained from an examination of this preserved material. 



Sexually mature specimens, well extended, average about 

 50 mm. in length and 1 mm. in diameter at the tenth somite, 

 where the diameter is greatest. The body gradually decreases 

 in diameter toward the posterior end, where the somites are 

 relatively smaller and less distinct. The anterior end termi- 

 nates in a proboscis about .15 mm. in length, its diameter 

 being .07 mm. at the base and .035 mm. at the middle. In 

 these preserved specimens it is bent upwards. In five appar- 

 ently complete individuals the number of somites varies from 

 155 to 177, the average number being 167. 



The clitellum extends from the anterior part of VIII to the 

 middle of XII, and is developed on the ventral surface. The 

 spermiducal pores are on the ventral side of IX (PI. XLL, 

 Fig. 1) ; the oviducal pores are in the groove between somites 

 X and XI and in line with the ventral setas ; and the sperm- 

 athecal pores are on the ventral side of VIII, a short dis- 

 tance posterior to the ventral setae of that somite. It will be 

 noted that the external openings of the reproductive organs 

 are further forward by one somite than is usual in the Lum- 

 briculidce. The three sectioned specimens which form the 



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