[1] The Chilopoda and Diplopoda are sometimes regarded as forming a single class—Myriopoda.

[2] The account given here of the structure of the Lobster applies almost equally well to the River Crayfish or the Norway Lobster. The student is recommended to follow the description with a specimen of one of these animals before him.

[3] I am indebted to Mr. J. T. Cunningham for calling my attention to some of the facts here recorded.