ASTEROID (Gr. aster, a star; and eidos, form).  Star-shaped, or possessing radiating lobes or rays like a star-fish.

ASTEROIDEA.  An order of Echinodermata, comprising the Star-fishes, characterised by their rayed form.

ASTEROPHYLLITES (Gr. aster, a star; phullon, leaf).  A genus of Palaeozoic plants, with leaves in whorls.

ASTRAEIDAE (Gr. Astroea, a proper name).  The family of the Star-corals.

ASTYLOSPONGIA (Gr. a, without; stulos, a column; spoggos, a sponge).  A genus of Silurian Sponges.

ATHYRIS (Gr. a, without; thura, door).  A genus of Brachiopods.

ATRYPA (Gr. a, without; trupa, a hole).  A genus of Brachiopods.

AVES (Lat. avis, a bird).  The class of the Birds.

AVICULA (Lat. a little bird).  The genus of Bivalve Molluscs comprising the Pearl-oysters.

AXOPHYLLUM (Gr. axon, a pivot; phullon, a leaf).  A genus of Rugose Corals.

AZOIC (Gr. a, without; zoe, life).  Destitute of traces of living beings.

BACULITES (Lat. baculum, a staff).  A genus of the Ammonitidoe.

BALAENA (Lat. a whale).  The genus of the Whalebone Whales.

BALANIDAE (Gr. balanos, an acorn).  A family of sessile Cirripedes, commonly called “Acorn-shells.”

BATRACHIA (Gr. batrachos, a frog).  Often loosely applied to any of the Amphibia, but sometimes restricted to the Amphibians as a class, or to the single order of the Anoura.

BELEMNITIDAE (Gr. belemnon, a dart).  An extinct group of Dibranchiate Cephalopods, comprising the Belemnites and their allies.

BELEMNOTEUTHIS (Gr. belemnon, a dart; teuthis, a cuttle-fish).  A genus allied to the Belemnites proper.

BELINURUS (Gr. belos, a dart; oura, tail).  A genus of fossil King-crabs.

BELLEROPHON (Gr. proper name).  A genus of oceanic Univalves (Heteropoda).

BELOTEUTHIS (Gr. belos, a dart; teuthis, a cuttle-fish).  An extinct genus of Dibranchiate Cephalopods.

BEYRICHIA (named after Prof.  Beyrich).  A genus of Ostracode Crustaceans.

BILATERAL.  Having two symmetrical sides.

BIMANA (Lat. Bis, twice; manus, a hand).  The order of Mammalia comprising man alone.

BIPEDAL (Lat. bis, twice; pes, foot).  Walking upon two legs.

BIVALVE (Lat. bis, twice; valvoe, folding-doors).  Composed of two plates or valves; applied to the shell of the Lamellibranchiata and Brachiopoda, and to the carapace of certain Crustacea.

BLASTOIDEA (Gr. blastos, a bud; and eidos, form).  An extinct order of Echinodermata, often called Pentremites.