496 



GLOSSARY 



Antler-royal, the third branch of a Red Deer's 



antler (counting' from its base). 

 Aorta (Gk. a^iro^ I carry), the chief artery of 



the bod}'. 

 Aortic arches, the arteries \vhlch traverse the 



visceral arches of Vertebrates. 

 Apical disc, in Echlnoderms (especially sea- 

 urchins), a double circlet of plates on the 



upper surface of the body. 

 Apiculture (L. apis^ a bee), bee-culture. 

 Apteria (Gk. a, without; pteryKn a feather), 



featherless patches of a Bird's skin. 

 Arch, of a vertebra (or joint of the backbone), 



the dorsal part which forms the roof and 



sides of the hole traversed by the spinal 



cord. 

 Archenteron (Gk. arche^ a beg-inning;; eiiteron^ 



an intestine), the digestive cavity of the 



Gastrula (which see). 

 Area of distribution, area inhabited by a 



species or other animal group. It is discon- 



timious if consisting of two or more isolated 



portions. 

 Artery, a blood-vessel which carries blood 



froni the heart. 

 Articular processes, projections on the arches 



of vertebrae, by which these are connected 



together. 

 Artificial selection, the production of breeds 



ot domesticated animals by human agency. 

 Assimilation (L. adsimilo, I make like), the 



conversion of digested food into body-sub- 

 stance. 

 Atavism (L. atavus, an ancestor). See Rever- 



sio7i. 

 Atlas, the ring-shaped first vertebra of the 



neck-region. 

 Atoll, a ring-shaped coral island. 

 Atrial cavity (L. atrium, a hall), a space sur- 

 rounding most of the pharynx in Lancelets 



and Ascidians. 

 Atriopore, the opening of the Atrial cavity 



(which see). 

 Auricle (L. auricula^ a little ear), a relatively 



thin-walled heart-chamber, into which veins 



pour blood. 

 Auricularia, pi. -ae (L. for lobe of the ear), in 



Sea-Cucumbers, a bilateral larva, provided 



with a sinuous ciliated band, suggesting the 



appearance of an ear in side-view. 

 Australian region, Australia and adjacent 



islands, with eastern part of East Indies, 



New Zealand, and Polynesia. 

 Axis, the second neck-vertebra. 



Balancers (halteres), small club-shaped struc- 

 tures representing the reduced hind-wings in 

 Flies. 



Baleen ("whalebone"), in toothless Whales, 

 elastic plates hanging down from the roof 

 of the mouth. 



Barb, one of the flattened branches borne by 

 the axis of a feather. 



Barbel, one of the sensitive filaments with 



which the mouth-region is provided in some 

 Fishes, e.g: Cat-Fishes. 



Barbule, one of the small branches borne by 

 the barbs of a feather. 



Bastard-wing (ala spuria), a tuft of feathers 

 borne by the thumb of a bird. 



Beche-de-mer, Trepang (which see). 



Bedeguar, a tufted gall on the I'ose, produced 

 by the attack of a Gall-Fly. 



Beneficials, those wild animals that by their 

 habits promote the welfare of mankind. 



Benthos (Gk. b^^nthos, depth), the assemblage 

 of animals inhabiting deep water. 



Bez-tine, the second branch of a Red Deer's 

 antler (counting from Its base). 



Biconcave, hollow on both sides, e.g. the ver- 

 tebra of a Fish. 



Bicuspid. See Premolar. 



Bilateral Symmetry. See Symmetry. 



Bile, or Gall, the secretion of the liver. 



Bile-duct, a tube through which bile passes 

 into the intestine. 



Biology (Gk. bios^ life; logos, a discourse), the 

 science of life. 



Bipinnaria, pi. -ae, in Star-Fishes, the bilateral 

 larva, which is provided with pairs of soft 

 ciliated arms. 



Bivalve, applied to the shell of a Mollusc when 

 made up of two pieces or valves, e.g. In a 

 Mussel. Lamp-shells (Brachlopoda) are also 

 bivalve, and Mussel - Shrimps (Ostracoda) 

 possess a bivalve shield or sheik 



Blastopore (Gk. blastos, a germ ; pora, a pas- 

 sage), the mouth of a Gastrula (which see). 



Blastosphere (Gk. blastbs., a germ; sphaira^ 

 a sphere), a hollow and spheroidal kind of 

 Blastula (which see). 



Blastula (Gk. dim. of blastos, a germ), the 

 embryonic stage resulting from Cleavage 

 (which see). 



Blight, a disease of plants, often due to the 

 presence of aphides. 



Blubber, in marine Mammals, a thick layer of 

 fat below the skin. 



Body - cavity, in animals higher than Zoo- 

 phytes, a space or series of spaces between 

 the internal organs and body-wall. 



Botany (Gk. botane, a plant), the science deal- 

 ing with plants. 



Bouchot, In mussel-culture, a collector made 

 of stakes with interwoven twigs. 



Brachiolaria, pi. -as, a variety of the Bipin- 

 naria (which see). 



Bronchus, pi. -i, one of the two main branches 

 of the wind-pipe. 



Brood -parasitism, used of animals {e.g. the 

 Cuckoo) which evade the responsibility of 

 bringing up their own young. 



Brow-tine, the lowest branch of a Red Deer's 

 antler, projecting over the forehead. 



Byssus (Gk. byssos), adhesive threads by which 

 some Bivalve Molluscs attach themselves. 



