240 The Irish Naturalist. 



worm has happily passed through the hands of systematists invari- 

 ably as Lniiibricus ciseni, Levinsen ; but the time has come when it must 

 be removed from the false position it has occupied undisturbed till the 

 present. It must, however, be admitted that it does not fit in with the 

 genus Allolobophora, though it belongs to this place as a true tree- worm. 



The worm is small, cylindrical, slightly attenuated, usually about an inch, 

 or at most an inch and a half, in length, i.e., 30 to 40 millimetres. Its 

 prostomium, like that of the true Lnnibricus, forms with the peristomium 

 a perfect mortise and tenon. It often closely resembles the typical 

 LtiDibriais in colour, being a warm brown, frequently with iridescence, and 

 has the setae in couples somewhat closer together. These are its only 

 affinities in that direction. It lives in old trunks of trees and among 

 decaying timber or woodland debris, is small, destitute of the two pairs 

 of spermathecse which every true Lwiibricus possesses, and in the matter 

 of clitellum and its accessories is separated very widely from that genus. 



The girdle covers eight segments, extending from 24 to 31 ; total number 

 of segments, 90-110. There are no tiLberciila piibertatis ; the male pore on 

 segment 15 is on papillae slightly developed, and the first dorsal pore is 

 between 5 and 6. The constancy of this feature in the dendrobaenic 

 group is striking. Rosa submitted specimens exactly answering this 

 descriptions to Levinsen, who stated that they were identical with his 

 Liwibi'icus ciseni.'^ The original specimens from Copenhagen were taken, 

 according to Rosa's translation of Levinsen's account, from old trees, and 

 my British specimens have been obtained from similar habitats. 



Synonym: Ltunbricus eisini, Levinsen (Syst. geogr. Oversigt over de nord. 

 Ann. &c., Copenhagen, 1883). A. eiseni, Rosa, 1893. Dr. Rosa has done 

 me the honour to place on record the fact that I was the first to assign 

 this curious worm to its rightful place. 



Distribution in Irei^and.— Woodenbridge, Co. Wicklow (Dr. Scharft); 

 Valencia, Co. Kerry (Miss Delap) ; Malahide, Co. Dublin (Dr. Trumbull) ; 

 Carrablagh, Lough Swilly (Mr. Hart); Leeson-park, Dublin (Dr. Scharff). 



We are now prepared for a survey of the principal characteristics, of 

 the group. 



\ Dkndrob^na, Eisen. 



Small tender worms, from i to 2| inches in length, found in decaying 

 trees, among dead leaves, and rotten vegetable matter ; sometimes 

 wandering to other habitats. Colour usually brown, rose-red or flesh, 

 with dull clitellum and lighter-under-surface. Prostomium more or less 

 deeply imbedded in the peristomium, which is without setae. Setae 

 always in eight rows or in four couples, more or less distant, making the 

 body appear octangular. 



Girdle occuping five to eight segments, commencing somewhere 

 between the 24th and 31st. 



Male or spermiducal pores on segment 15, usually with prominent 

 papillae, which sometimes extend over the two adjoining segments. 



Tiibercula ptibertatis in two or three pairs on consecutive segments; not 

 observed in one species. 



First dorsal pore usually between segments 5 and 6. Sperniatophores 

 between the male pore and the clitellum. 



The internal characters have not yet been made out with sufficient 

 accuracy by any investigator to allow of classification. Spermathecae 

 are present in some species, but absent from others. When present 

 they are open in the direction of the superior pair of setae (Rosa). 



Usually secreting a small quantity of yellow fluid from the dorsal 

 pores. 



The accompanying table supplies in concise form the principal distin- 

 guishing features of this interesting group of worms. 



' Bolletino Mus. Zool. ed Anat. 1S87, 1889. 



