GLOSSARY. 565 



ASCIDIOIDA (Gr. asJcos, a bottle ; eidos, a form). A synonym of Tunicata, a 

 class of Molluscous animals, which have the shape, in many cases, of a 

 two-necked bottle. 



ASEXUAL. Applied to modes of reproduction in which the sexes are not 

 concerned. 



ASIPHONATE. Not possessing a respiratory tube or siphon. (Applied to a 

 division of the Lamellibranchiate Molluscs). 



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, char- 

 acterised by their rayed form. 



ASTOMATOUS (Gr. a, without; stoma, mouth). Not possessing a mouth. 



ATLAS (Gr. the God who holds up the earth). The first vertebra of the neck, 

 which articulates with and supports the skull. 



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. 



AZYGOUS (Gr. a, without ; zugon, yoke). Single ; without a fellow. 



BALANID^E (Gr. balanos, an acorn). A family of sessile Cirripedes, commonly 

 called "Acorn- shells." 



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

 of the true or " whalebone" Whales. 



BATIDFS (Gr. bates, a bramble). The family of the Elasmobranchii comprising 

 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. 



BELEMNITID^E (Gr. belemnon, a dart). An extinct group of Dibranchiate 

 Cephalopods, comprising the Belemnites and their allies. 



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. 



BIVALVE (Lat. bis, twice ; valvce, 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 Echi- 

 nodermata, often called Pentremites. 



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

 coida, 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). 



BRADYPODIDJE (Gr. bradus, slow ; podes, 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 braiichiaB. 



BRANCHIFERA (Gr. bragchia, gill; andphero, I carry). A division of Oaslero- 

 podous Molluscs, 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, I cover). Applied to a membrane 

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



