Search the Dictionary

ch articulates with the tibia and corresponds to a part of the astragalus in man and most mammals.

An extinct group of Mammalia found fossil in the Eocene formation. The species are related to the carnivores, ungulates, and rodents. Called also Tillodonta.

A large American Miocene mammal, allied to the rhinoceros, and more nearly to the extinct Brontotherium.

A gigantic extinct herbivorous mammal from South America, having teeth bent like a bow. It is the type of the order Toxodonta.

An extinct order of Mammalia found in the South American Tertiary formation. The incisor teeth were long and curved and provided with a persistent pulp. They are supposed to be related both to the rodents and ungulates. Called also Toxodontia.

flaps, at the opening of the right auricle into the right ventricle in the heart of most mammals; -- sometimes called the tricuspid valves, each flap being regarded as a valve.

A theory of the development of mammalian molar teeth. The primitive stage is that of simple cones, as in reptiles. The simple cone then developed a smaller cone in front and another behind. Next, a cingulum was developed, and the three cones became arranged in a triangle, the two smaller cusps having moved to the outer…

ilk is secreted and stored; -- popularly called the bag in cows and other quadrupeds. See Mamma. A lioness, with udders all drawn dry. Shak.

An extensive division of Mammalia including those having claws or nails, as distinguished from the hoofed animals (Ungulata).

An extensive group of mammals including all those that have hoofs. It comprises the Artiodactyla and Perissodactyla.

A very soluble crystalline body which is the chief constituent of the urine in mammals and some other animals. It is also present in small quantity in blood, serous fluids, lymph, the liver, etc.

id. Uric acid, a crystalline body, present in small quantity in the urine of man and most mammals. Combined in the form of urate of ammonia, it is the chief constituent of the urine of birds and reptiles, forming the white part. Traces of it are also found in the various organs of the body. It is likewise a common cons…

In mammals, a fluid excretion from the kidneys; in birds and reptiles, a solid or semisolid excretion.

The organ of a female mammal in which the young are developed previous to birth; the womb.

nd a ventral, or visceral, cavity below it. The subdivisions or classes of Vertebrata are Mammalia, Aves, Reptilia, Amphibia, Pisces, Marsipobranchia, and Leptocardia.

A South American mammal (Auchenia vicunna) native of the elevated plains of the Andes, allied to the llama but smaller. It has a thick coat of very fine reddish brown wool, and long, pendent white hair on the breast and belly. It is hunted for its wool and flesh.

Producing young in a living state, as most mammals, or as those plants the offspring of which are produced alive, either by bulbs instead of seeds, or by the seeds themselves germinating on the plant, instead of falling, as they usually do; -- opposed to oviparous. Viviparous fish. (Zoöl.) See Embiotocoid. -- Viviparo…

f the skull, forming a part a part of the partition between the nostrils in man and other mammals.

A very large marine mammal (Trichecus rosmarus) of the Seal family, native of the Arctic Ocean. The male has long and powerful tusks descending from the upper jaw. It uses these in procuring food and in fighting. It is hunted for its oil, ivory, and skin. It feeds largely on mollusks. Called also morse.…

Having warm blood; -- applied especially to those animals, as birds and mammals, which have warm blood, or, more properly, the power of maintaining a nearly uniform temperature whatever the temperature of the surrounding air. See Homoiothermal.