Maas, loc. cit. p. 284.
J. Coll. Japan, xv. 1901, p. 180.
Perkins, Johns Hopkins Univ. Circ. xxi. 1902, p. 87.
For details of this interesting process see Minchin, Quart. J. Micr. Sci. xl. 1898, p. 469.
Maas, Zeitschr. wiss. Zool. lxvii. 1900, p. 225.