020 



This is not only the first record of a species of Marionina for 

 Ilhnois, but it is also the first time a representative of this genus has 

 been reported from the United States, although Eisen ('05) has 

 described two new species from Alaska. 



The genus Alarionina was established by Michaelsen in 1889. 

 Previous to that time forms belonging to this genus were scattered 

 among a number of the older genera, the old genus Pachydrilus 

 {Litinbricilliis) receiving the larger part. 



Michaelsen ('00, p. 73) defines the genus Marionina as follows: 

 "Borsten S-formig gebogen. Riickenporen fehlen; Kopfporus klein, 

 zwischen Kopflappen und i. Segm. Das Ruckengefass entspringt 

 postclitellial und besitzt kein Herzkorper. Peptonephridien fehlen. 

 Hoden massig. Samenleiter lang. Samentaschen ohne Divertikel." 

 Eisen ('05, p. 90) has extended this definition somewhat: "Setae 

 sigmoid, as in Lumbricillus. Head pore small, between the prosto- 

 mium and somite I. No dorsal pores. Blood red or yellow. Dorsal 

 vessel rises posterior to clitellum. No cardiac gland. No peptone- 

 phridia. Spemi-ducts comparatively long and narrow. Penial bulb 

 without interior muscular strands. Testes undivided, each covered 

 with a small sperm-sac. Ventral glands present or absent. Nephridia 

 with entire postseptal and with comparatively large head-like ante- 

 septal." 



The close similarity between the definition of Marionina and that 

 of Lumbricillus is apparent, the chief difference being the presence 

 of multilobed testes in the latter. Eisen ('05, p. 90) thinks that an- 

 other difference may be derived from the nephridium, "which in 

 Marionina seems to be characterized by a long head-like anteseptal, 

 while in Lumbricillus the anteseptal consists of merely the nephro- 

 stome." There are insufficient grounds for giving such a character 

 generic rank, since the anteseptal part of the nephridium in Marionina 

 is quite variable. In M. werthi Mchlsn., M. falclandica Mchlsn., and 

 in several other species, the anteseptal part consists of the nephro- 

 stome only. 



Marionina is one of the smaller genera of the family BncJiy- 

 trccidcc. At present twenty-six apparently valid species are assigned 

 to it, of which only two have been recorded for North America. 

 They are M. alaskce Eisen and M. americana Eisen, both from Port 

 Clarence, Alaska. 



Marionina forees.i; n. sp. 



Definition. — Length, 5-6 mm. Diameter, 0.221-0.238 mm. 

 Somites, 25-28. Setae slightly sigmoid ; those of a bundle equal in 

 size ; 2-4 per bundle. Clitellum on XII-XIII ; developed only on 



