The scattered literature of this family is due to Benham, Michaelsen, Perrier, Rosa, and others.
Rosa, "Revisione dei Lumbricidae," Mem. Acc. Torino (2), xliii. 1893, p. 399; also the Rev. H. Friend's numerous and useful papers, and especially "A New Species of Earthworms," Proc. Roy. Irish Ac. (3) ii. 1891-93, p. 402; and "The Earthworms of Ireland," Irish Nat. v. 1896, p. 69, etc.
In the tables the figures refer to the segments of the body. Opposite the name of each species are two sets of lines; the upper series indicate the segments occupied by the clitellum; the lower series those occupied by the tubercula pubertatis. The dots indicate the occasional extension of the clitellum or of the tubercula.
"Annelés," vol. iii. 1889-90, p. 477, in the Suites à Buffon.
See v. Kennel, Zool. Jahrb. ii. 1887, p. 37.