GLOSSARY. 669 



AsciDiAN. (Gr. ashos, a bottle.) The shell-less acephalous Mollusks, which are 



sliai:)ed like a leathern bottle. 

 Assimilation. (Lat. assimilatio.) The act by which organised bodies incorporate 



foreign molecules and convert them into their own proper substance. 

 AsTOMATOus. (Gr. a, without ; stoma, a mouth.) Certain Infusoria Avhich have 



no true or determinate mouth. 

 Atol. The name given by the Polynesians to certain forms of coral islands. 

 Automatic. (Gr. automatos, self-moving.) A movement in a living body without 



the intervention or excitement of the will. 

 Axilla (from the Latin for armpit) ; and applied to other parts of the animal body 



which form a similar angle. 

 AzYGOS. (Gr. a, without ; zugos, yoke.) Single, without fellow, 



Baculite. An extinct genus of molluscous animals allied to the Nautilus, which 



inhabited a straight-chambered shell, resembling a staff; whence the name of 



the genus, from baculus, a staff. 

 Balanoids. (Gr. balanos, an acorn.) A family of sessile Cirripeds, the shells of 



which are commonly called acorn-shells. 

 Basilar. (Lat. basis, a base.) Belonging to the base of the skull. 

 Batrachia. (Gr. batrachos, a frog.) The order of reptiles including the fi'og. 

 Belemnite. (Gr. belemnon, a dart.) An extinct genius of molluscous animals 



allied to the sepia, and provided with a long, straight, chambered, conical shell in 



the interior of the body. 

 Bifid. Cleft into two parts, or forked. 

 Bifurcate. Divided into two prongs or forks. 

 Bilateral. Having two symmetrical sides. 

 Bilobed. Divided into two lobes. 

 Bipartite. Divided into two parts. 



BiRAMOUS. A limb which forks into two oar-like extremities. 

 Bituberculate. With two knobs or tubercles. 

 Bivalve. When a shell consists of two parts, closing like a double door. The 



MoUusca, so protected, are commonly called bivalves. 

 Botiiriocephalds. (Gr. bothros, a pit; kephale, a head.) The genus of tape-worms 



Avith depressions on the head. 

 BoTRYLLi. (Gr. botrus, a bunch of grapes.) A little cluster of berry-shaped 



bodies. 

 Brachial. (Gr. brachion, the arm.) Belonging to the arm. 

 Brachiopoda. (Gr. brachion ; poda, feet.) A class of acephalous Mollusca, with 



two long spiral fleshy ai'ms continued from the side of the mouth. 

 Brachyura. (Gr. brachus, short ; aura, tail.) The tribe of Crustacea with short 



tails, as the crabs. 

 Brachydrous. Short tailed ; usually restricted to the Crustacea. 

 Braxchia. (Gr. bragchia, the gills of a fish.) The respiratory organs which 



extract the oxygen from air contained in water. 

 Branchiopods. (Gr. bragchia, gills ; />o(/a, feet.) Crustacea in which the feet sup- 

 port the gills. 

 Bryozoa. (Gr. Srwow, moss ; 2:oon, animal.) A class of highly-organised Polypes, 



most of the species of which incrust other animals or bodies like moss. 

 Buccal. (Lat. bucca, mouth or cheeks.) Belonging to the mouth. 

 Byssus (from the Greek word, signifying the silky filaments which project from the 



bivalve called Pinna). Applied to the analogous parts in other Mollusks. 



CuECUM and C^ca. (Lat. coecus, blind.) A blind tube, or productions of a tube 



which terminate in closed ends. 

 Canthus. (Cty. (Jianthos.) The corner of the eye. 

 Capitate. (Lat. caput, head.) When a part is terminated by a knob like the 



head of a pin. 

 Carapace. The upper shell of the crab or tortoise. 

 Cardia. (Gr. kardia, the heart or stomach.) The opening which admits the food 



into the stomach ; also the region called the pit of the stomach. 

 Carnivorous. (Lat. caro, flesh; voro, I devour.) The animals which feed on flesh. 



