"Introduction to the Study of Fishes." Albert Gunther. A. & C. Black, Edinburgh.

On Insects.

See the end of Chapter XLIV.

On Invertebrates.

"The Ocean World." Louis Figuier. Cassell & Co., New York. $2.50.

"Recent and Fossil Shells." S.P. Woodward, London. John Weale, 1856. (Apply to Bernard Quaritch, London.)

A very handy and useful manual for the field. Many illustrations. Price about $1.50.

"Structural and Systematic Conchology." Geo. W. Tryon. Philadelphia Academy of Natural Sciences. $12.00.

A great work; complete, exhaustive, and richly illustrated.

For Suggestions of Groups of Animals.