194 BACKBONED ANIMALS. 
alike and opposite each other, the caudal fin seemingly a 
mere projective rim of the entire hinder part of the body. 
Powerful muscles lead into it, but it is probably of little 
use in locomotion. 
Specimens for Study—The habits and exterior parts of 
fishes can be studied from minnows, sunfish, stickle- 
backs, etc., kept in an aquarium or a glass vessel of any 
kind provided with aquatic plants to aérate the water. 
Dissections of small specimens are best made in a dish 
under water, when each part shown in Fig. 194 should be 
determined. With a delicate knife, the various organs can 
be exposed, as the brain, nostrils, ears, etc. In preparing 
a first skeleton, boil the fish, and reconstruct the skeleton 
as well as possible by (Fig. 193) marking all the parts and 
observing their relations one to another. In studying the 
circulation, inject into the veins some colored fluid, as ver- 
milion. It is extremely important to make.a drawing of 
the fish or its parts. 
Works on Fishes for further reference. 
“Challenger Reports”; “ Game-Fishes of the United States,” 
Killbourne text, by G. Brown Goode ; “American Fauna,” by J. 
B. Holder, M.D.; “ Fishes of Massachusetts,” Storer ; Goode and 
Bean, “ List of Fishes of Massachusetts Bay and Adjacent Waters,” in 
‘Bulletin of the Essex Institute,” vol. ii; “ Reports of the United 
States Commissioner of Fisheries and Various State Commissioners ” ; 
“Skates’ Eggs and Young,” F. W. Putnam, “ American Naturalist,” 
vol. iii, p.617; “ Gar-Pikes, Old and Young,” B. G. Wilder, “ Popular 
Science Monthly,” vol. ii; “ Respiration of Amia,” B. G. Wilder, 
“ Proceedings of the American Association for the Advancement of 
Science,” 1877, also in “ Popular Science Monthly”; “ Blind Fishes 
of the Mammoth Cave,” ‘* American Naturalist,” vol. vi, p. 6, and 
“Report of Peabody Academy of Science,” 1871; ‘‘ List of Fresh- 
Water Fishes of North America,” D. S. Jordan, ‘‘ Bulletin of thé Buf- 
falo Academy of Natural Science,” vol. iii ; ‘‘ Introduction to the Study 
of Fishes,” Gunther; ‘“ Development of Osseous Fishes,” Agassiz, 
“ Proceedings of the American Academy of Arts and Sciences,” vol. 
xiv ; and the works of Brehm, Wood, and Cassell. 
