[275]

Carter and Lieberkühn in 1856, Haeckel in 1872, Metschnikoff in 1879, and many later workers.

[276]

Die Kalkschwämme, 1872, i. p. 372.

[277]

J. Anat. Physiol. 1898, pp. 1, 6, 234.

[278]

Mém. Ac. St. Pétersb. (7) xxvi. 1878, p. 10.

[279]

Sollas, Challenger Report, xxv. pt. lxiii. p. lxxxviii.