The absence of these fishes from the United States west of the Rocky Mountains is very remarkable. Amiurus nebulosus was introduced about 1877 into some parts of California, where it is said to be now excessively abundant.

[672]

Cf. Sörensen, C. R. Ac. Sci. lxxxviii. 1879, p. 1042, and "Lydorgane hos Fiske" (Copenhagen, 1884); Bridge and Haddon, P.R.S. lv. 1894, p. 439.

[673]

Cf. Hancock, Zool. Journ. iv. 1829, p. 242.

[674]

Cf. G. Fritsch, "Die Elektrischen Fische, I. Malopterurus" (Leipzig, 1887); E. Ballowitz, "Das elektrische Organ des Afrikanischen Zitterwelses" (Jena, 1899).

[675]

Cf. Eycleshymer, Amer. Nat. 1901, p. 911.

[676]