142 



z'iridis, which is typically lumbricillid in all respects except that the 

 setae in the anterior part of the body have the form typical of 

 Enchytrcciis and that in the posterior part they show only a faint 

 double curve. He also described a new species from the same gen- 

 eral locality, Enchytrcciis nodosus, which, though unquestionably an 

 Bnchytrcens, has the following lumbricillid characters : ventral glands, 

 a compact penial bulb, and, in certain cases, a slight double curve of 

 the setae. Again, Bnchytrcciis diihiiis, a new species described from 

 the same general locality, has setae typical of the genus Bnchytrccus 

 but has ventral glands, a compact penial bulb ("although it is bifid 

 internally"), and lobed testes which resemble those in Lumhricillus. 

 It also has red blood. It may be added that Enchytrcciis albidus Henle, 

 a ver}' typical species of that genus, has an imperfect penial bulb 

 surrounded by other and smaller aggregations of gland cells. All 

 of these facts are interesting, since heretofore these two genera have 

 been regarded as standing some distance apart and have been placed 

 in different subfamilies. This point will be discussed in greater detail 

 in another connection (p. 178). 



Michaelsen ('00) assigned seventeen species to this genus, one of 

 which he regarded as somewhat doubtful. Later ( '03b) he added L. 

 henkingi Ude to the list, making a total of eighteen species, none of 

 which had been reported from North America. Recent investigations 

 have increased the number, so that at present thirty-one species, three 

 varieties, one doubtful species, and one doubtful variety are assigned 

 to this genus. Of this number six species and three varieties have been 

 described from North America. They are as follows, the type lo- 

 cality being also given: L. santccclarcc Eisen (San Mateo County, 

 California), L. nicrriaini Eisen (^^letlakatla, Alaska), L. nicrriaini, 

 var. elongatiis Eisen (Metlakatla, Alaska), L. annulatus Eisen (Met- 

 lakatla, Alaska; also Orca, Prince William Sound), L. ritteri Eisen 

 (Farragut Bay, Alaska), L. franciscamts Eisen (Santa Clara River, 

 California), L. franciscanns, var. horealis Eisen (St. Paul Island, 

 Pribilof group, Alaska), L. franciscanus, var. iinalaskcc Eisen (Una- 

 laska), and L. agilis Moore (Casco Bay, Me., to Vineyard Sound, 

 Mass.). L. riitihis, n. sp., is described in the following pages. 



Kev to the Species of Lumbricillus known to occur in 

 North America 



1 (6) Spermatheca with crown of glands limited to the ectal opening. 



2 (3) Spermathecal duct distinctly set off from ampulla ; ventral glands 



in XIV— XV; brain two and one half times longer than wide, 

 posterior margin deeply emarginate , santceclaroB 



3 (2) Spermathecal duct not distinctly set off from ampulla. 



