[635] Faull 1911.

[636] Dawson 1900.

[637] Brooks 1910.

[638] Blackman and Welsford 1912.

[639] Lindau 1899.

[640] Van Tieghem 1891.

[641] Zukal 1895.

[642] Wainio 1890.

[643] Steiner 1901.

[644] [See also Chap. VII.]