[2]

Gegenbaur, Grundzüge vergl. Anat. 2 ed. 1870, p. 158.

[3]

Lankester, Quart. J. Micr. Sci. xvii. 1877, p. 448 (= Aspidophora, Allman, J. Linn. Soc. xiv. 1879, pp. 490 n., 586).

[4]

Spengel, Zool. Jahrb. Syst. xv. 1902, p. 209.

[5]

Fauna u. Flora G.v. Neapel, 18 Monogr. 1893 (reviewed by MacBride in Quart. J. Micr. Sci. xxxvi. 1894, p. 385); Zool. Jahrb. Anat. xviii. Pt. ii. 1903, p. 271.

[6]

Quart. J. Micr. Sci. xxiv. 1884, p. 208; xxv. Suppl. 1885, p. 81; xxvi 1886, pp. 511, 535.