See Bürger, quoted on p. [403].
Loc. cit.
Quart. J. Micr. Sci. xxiv. 1884, p. 419; see also ibid. xxxiv. 1893, p. 545, which is mainly a criticism of Bolsius' additions to the very considerable literature upon the Leech nephridium.
"Spermatophores as a Means of Hypodermic Impregnation," J. Morphol. iv. 1891, p. 361.
Zeitschr. wiss. Zool. lviii. 1894, p. 440; and Zool. Jahrb. Anat. iv. 1891, p. 697.