Bourne, A. G. (1891). Notes on the Naidiform Oligochaeta; containing a description of New Species of the Genera, Pristina and Pterostylarides, and remarks upon Cephalization and Gemmation as generic and specific Characters in the Group.
Quarterly Journal of Microscopical Science. 32: 335-356 + Plates XXVI-XXVII.