GLOSSARY. 575 



AURELIA (Lat. aurum, gold). Applied to the chrysalides of some Lepidoptera, 



on account of their exhibiting a golden lustre. 

 AURICLE (Lat. dim. of auris, ear). Applied to one of the cavities of the 



heart, by which blood is driven into the ventricle. 

 AUTOPHAGI (Gr. autos, self; phago, I eat). Applied to birds whose young 



can run about and obtain food for themselves as soon as they escape from 



the egg. 



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

 AVICULARIUM (Lat. avicula, dim. of avis, a bird). A singular appendage, 



often shaped like the head of a bird, found in many of the Polyzoa. 

 Axis (Gr. axon, a pivot). The second vertebra of the neck, upon which the 



skull and atlas usually rotate. 

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



BACTERIUM (Gr. bakterion, a staff ). A kind of staff-shaped filament which 

 appears in organic infusions after they have been exposed to the air. 



BALANID^B (Gr. balanos, an acorn). A family of sessile Cirripides, com- 

 monly called " Acorn-shells." 



BALEEN (Lat. balcena, a whale). The horny plates which occupy the palate 

 of the true or " whale-bone" Whales. 



BATIDES (Gr. batos, a bramble). The family of the Elasmobranchii compris- 

 ing the Rays. 



BATRACHIA (Gr. batrachos, a frog). Often loosely applied to any of the Am- 

 phibia, but sometimes restricted to the Amphibians as a class, or to the 

 single order of the Anoura. 



BIFID. Cleft into two parts ; forked. 



BILATERAL. Having two symmetrical sides. 



BIMANA (Lat. bis, twice; manus, a hand). The order of Mammalia compris- 

 ing Man alone. 



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



BIRAMOUS (Lat. bis, twice ; ramus, a branch). Applied to a limb which is 

 divided into two branches (e.g., the limbs of Cirripedes). 



BIVALVE (Lat bis, twice ; valvee, 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. blasfos, a bud ; and eidos, form). An extinct order of Echi- 

 nodermata, often called Pentremites. 



BRACHIOPODA (Gr. brachion, an arm ; pous, the foot). A class of the Mol- 

 luscoida, often called " Lamp-shells," characterised by possessing two 

 fleshy arms continued from the sides of the mouth. 



BRACHIUM (Gr. brachion, arm). Applied to the upper arm of Vertebrates. 



BRACHYURA (Gr. brachus, short ; oura, tail). A tribe of the Decapod Crusta- 

 ceans with short tails (i.e., the Crabs). 



BRACTS. (See Hydrophyllia.) 



BRADYPODIDJE (Gr. bradus, slow; poda, feet). The family of Edentata com- 

 prising the Sloths. 



BRANCHIA (Gr. bragchia. the gill of a fish). A respiratory organ adapted to 

 breathe air dissolved in water. 



BRANCHIATE. Possessing gills or branchiae. 



BRANCHIFERA (Gr. bragchia, gill ; and phero, I carry). A division of Gastero- 

 podous Alolhiscs, in which the respiration is aquatic, and the respiratory 

 organs are mostly in the form of distinct gills. 



BRANCHIO-GASTEROPODA (= Branchifera). 



BRANCHIOPODA (Gr. bragchia; and pous, foot). A legion of Crustacea, in 

 which the gills are supported by the feet. 



BRANCHIOSTEGAL (Gr. bragchia, gill ; stego,! cover). Applied to a membrane 

 and rays by which the gills are protected in many fishes. 



BREVILINGUIA (Lat. brevis, short; lingua, tongue). A division of the Lacer- 

 tilia. 



BREVIPENNAT^! (Lat. brevis, short ; penna, a wing). A group of the Natato- 

 rial Birds. 



