viii PREFACE. 
each other would be a very great undertaking and cannot be prop- 
erly attempted at this time. Much additional knowledge, and in 
many cases a greater amount of material must be acquired before 
any considerable success in accurately determining the proper 
status of the numerously named forms can be obtained. 
The following is the arrangement adopted for the Orders and 
Families of the Mammalia comprised in this work, beginning with 
the lowest in degree: 
VOLUME IV.—PART I. 
ORDER I. MARrsuPIALIA—MARSUPIALS. 
Fam. 1. Didelphyidee—Opossums. 
ORDER II. Eprentata—EDENTATES. 
Fam. 1. Bradypodide—Sloths. 
Fam. 2. Myrmecophagida—Ant-eaters. 
Fam. 3. Dasypodide—Armadillos. 
ORDER III. Srrenra—SIReEnIans. 
Fam.1. Trichechida—Manatees. 
ORDER IV. CETAcCEA—CETACEANS. 
Fam. 1. Balaenide—Baleen Whales. 
Fam. 2. Physeterida—Sperm Whales. 
Fam. 3. Delphinidee—Dolphins, Porpoises, ete. 
ORDER V. UncGuLata—Hoorep QUADRUPEDS. 
Fam. 1. Tagassuida—Peccaries. 
Fam. 2. Cervide—Deer. 
Fam. 3. Antilocaprida—Prong-horn Antelopes. 
Fam. 4. Bovidae—Cattle, Sheep, etc. 
Fam. 5. Tapiride—tTapirs. 
ORDER VI. Ropent1A—RoODENTSs. 
Fam. 1. Sciuride—Squirrels. 
Fam. 2. Castoride—Beavers. 
Fam. 3. Murida—Rats, Mice, Voles. 
Fam. 4. Geomyide—Pouched Rats. 
Fam. 5. Heteromyide—Kangaroo Rats, Pocket Mice. 
Fam. 6. Octodontide—The Octodonts. 
Fam. 7. Erethizontida—Porcupines. 
Fam. 8. Agoutide—Agoutis, Pacas. 
Fam. 9. Leporidae—Hares, Rabbits. 
VOLUME IV.—PART II. 
ORDER VII. CARNIVORA—CARNIVORES. 
Fam. 1. Felide—Cats. 
Fam. 2. Viverride—Mungoose, Civets, etc. 
Fam. 3. Canide—Dogs, Wolves, Foxes. 
Fam. 4. Ursida—Bears. 
Fam. 5. Procyonide—Raccoons. 
Fam. 6. Mustelide—Badgers, Weasels, Otters, etc. 
ORDER VIII. PinnNipEpIA—PINNIPEDs. 
Fam. 1. Otariide—Sea-lions. 
Fam. 2. Phocidwe—Seals. 
