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The lowest group of Vertebrata, including the amphioxus, in which no skull exists.

A group of acalephs, including most of the larger jellyfishes; the Discophora.

The lowest groups of animals, in which no nervous system has been observed.

One of a group of lizards having the teeth immovably united to the top of the alveolar ridge. -- a. Of or pertaining to the acrodonts.

A group of Coelenterata, comprising the Anthozoa Ctenophora. The sea anemone, or actinia, is a familiar example.

(Anat.) Formed into clusters or groups of lobules; as, aggregate glands.

Grouped together; as, the agminated glands of Peyer in the small intestine.

A group of the Carnivora, which includes the cats, civets, and hyenas.

A group of soft-bodied Alcyonaria, of which Alcyonium is the type. See Illust. under Alcyonaria.

t magnitude, situated in the eye of Taurus; the Bull's Eye. It is the bright star in the group called the Hyades. Now when Aldebaran was mounted high Above the shiny Cassiopeia's chair. Spenser.

A group of birds including the common fowl and the pheasants.

The Algonkian period or era, or system or group of systems.

of the northern and eastern part of North America. The name was originally applied to a group of Indian tribes north of the River St. Lawrence.

n consisting of large whitish or grayish globular cloudlets with shaded portions, often grouped in flocks or rows.

A group of large, extinct, herbivorous mammals, common in the Tertiary formation of the United States.

A group of insects which do not undergo any metamorphosis. [Written also Ametabolia.]

atom or radical. Acid amide, a neutral compound formed by the substitution of the amido group for hydroxyl in an acid.

acid, an acid in which a portion of the nonacid hydrogen has been replaced by the amido group. The amido acids are both basic and acid. -- Amido group, amidogen, NH2.

e molecule of which one of its hydrogen atoms has been removed; -- called also the amido group, and in composition represented by the form amido.

An extensive group of fossil cephalopods often very abundant in Mesozoic rocks. See Ammonite.