GLOSSARY 



Tuberculated, possessing- tubercles. 



Tympanic (L. tympanum, a drum), connected 

 with the drum of the ear in air-breathing 

 Mammals. 



Tympanum (L. tympanum, a drum): (i) the 

 drum of the ear; (2) the cavity of the song-- 

 box (syrinx) of a bird. 



Ulna (L. for the elbow), the bone of the fore- 

 arm which is on the little finger side. 



Ulnare, a proximal element of the carpus, 

 situated on the side next the little finger. 



Umbo (L. umbo, the boss of a shield), the pro- 

 jecting- beak commonly possessed by each 

 half of a bivalve shell, and which is the 

 oldest part. 



Uncinate (L. uncinatus, hooked), hook-like. 



Unidactyle (L. unus, one; daktyltis, a finger 

 or toe), possessing one digit. 



Univalve, applied to the shell of a Mollusc, 

 when made up of only one piece or valve, as, 

 e.g., in a Snail. 



Ureter, a tube by which the urine is carried 

 off from a kidney. 



Urostyle (Gk. oura, a tail; styles, a pillar), 

 the bony rod which forms the hinder part of 

 a Frog's backbone. 



Vacuole (L. dim. of vacuum, an empty space), 

 in cells, a small space filled with liquid or 

 gas. Pulsating vacuole, in Animalcules, a 

 vacuole which alternately empties and fills 

 in a regular manner. 



Vagus nerves (L. vagus, wandering), the 

 tenth pair of cranial nerves, which run back 

 into the abdominal region. 



Valve (L. valva, a folding-door): (i) an ar- 

 rangement of one or more projecting flaps by 

 means of which food in the gut, blood in the 

 heart, &c. , are obliged to move forward ; 

 (2) a distinct piece of shell. See Bivalve 

 and Univalve. 



Vane, the projecting flat part of a feather. 



Variable aggressive coloration, in predaceous 

 forms, coloration which changes with the 

 surroundings so as to produce inconspicuous- 

 ness. 



Variation, the appearance of new characters 

 with the result that no two individuals of the 

 same species are exactly alike. 



Vegetative propagation, increase by methods 

 other than egg- production, e.g. by Gem- 

 mation, Fission, and Spore -formation 

 (which see). 



Vein, a blood-vessel which carries blood to or 

 towards the heart. 



Veliger (L. velum, a sail; gero, I carry), in 

 Molluscs, a shell-bearing larva with a large 

 ciliated head-flap by means of which swim- 

 ming is effected. 



Velum (L. for sail or veil), in some Jelly-fishes, 

 an inwardly projecting shelf at the edge of 

 the umbrella. 



Ventral (L. for the belly), applied to the under 

 side of an animal. 



Ventricle (the Latin name), a relatively thick- 

 walled and muscular heart-chamber, which 

 pumps blood into arteries. 



Vertebra, pi. vertebrae (the Latin name), one 

 of the joints of the backbone. 



Vertebral column, the backbone, or (in some 

 Fishes) its gristly equivalent. 



Vertebrate, applied to animals possessing a 

 backbone or its equivalent. 



Vestige, or Rudimentary organ, a structure 

 which has undergone reduction, as the result 

 of adaptation to surroundings. 



Vestigial, reduced to a Vestige (which see). 



Visceral, relating to the viscera. See Viscus. 



Visceral arches and clefts, thickenings and 

 slit-like openings on each side of the throat, 

 which are possessed by every Vertebrate for 

 at least part of its life. The clefts place the 

 pharynx in communication with the exterior. 



Visceral hump, the projecting upper part of 

 many Molluscs, containing many of the chief 

 internal organs. 



Viscus, pi. -era, one of the internal organs 

 contained in the chest or abdomen. 



Vitelline membrane, the membrane surround- 

 ing an egg-cell. 



Viviparous (L. vivus, alive ; pario, I produce), 

 giving birth to more or less well-developed 

 young, as opposed to egg-laying. 



Vocal chords, in Mammals, &c. ; two elastic 

 folds in the voice-box. A sound is emitted 

 when their edges are brought parallel and 

 thrown into vibration by an air-current. 



Wallace's Line, the boundary between the 

 Oriental and Australian regions. 



Wampum, the shell-money and ornaments of 

 North American Indians. 



Warbles, swellings on the backs of cattle, 

 caused by the presence of larval bot-flies. 



Warning coloration, crude colours and pat- 

 terns possessed by many inedible or well- 

 armed forms, and producing conspicuous- 

 ness. By advertising unpleasant properties 

 it reduces the chance of attacks by enemies. 

 Some forms are also protected by emitting 

 warning sounds, or assuming warning (or 

 terrifying) attitudes. 



Water -vascular system, in Echinoderms, 

 a system of tubes into which sea -water 

 enters. It is concerned with locomotion and 

 respiration. 



White matter, that part of the central nervous 

 system made up of nerve-fibres. 



Wing coverts, feathers covering the wing- 

 quills. 



Zebra-mule, a cross between Zebra and 

 Horse. 



Zoaea, pi. -3t (Gk. zoia, life), in higher 

 Crustaceans, a large -headed larva, swim- 

 ming by its foot-jaws, and possessing a limb- 

 less abdomen. 



Zoogeography (Gk. zoon, an animal), distri- 

 bution of animals in space. 



