406 GLOSSARY. 



ANIMALCULE. A minute animal : generally applied to those visible only by 



the microscope. 

 ANNELIDS. A class of worms in which the surface of the body exhibits a more 



or less distinct division into rings or segments, generally provided with 



appendages for locomotion and with gills. It includes the ordinary marine 



worms, the earthworms, and the leeches. 

 AXTEXXJE. Jointed organs appended to the head in Insects, Crustacea and 



Centipedes, and not belonging to the mouth. 

 ANTHERS. The summits of the stamens of flowers, in which the pollen or 



fertilising dust is produced. 



APLACENTALIA, APLACENTATA or Aplacental Mammals. See MAMMALIA. 

 ARCHETYPAL. Of or belonging to the Archetype, or ideal primitive form upon 



which all the beings of a group seem to be organised. 

 ARTICULATA. A great division of the Animal Kingdom characterised generally 



by having the surface of the body divided into rings called segments, a 



greater or less number of which are furnished with jointed legs (such as 



Insects, Crustaceans and Centipedes). 

 ASYMMETRICAL. Having the two sides unlike. 

 ATROPHIED. Arrested in development at a very early stage. 



BALANUS. The genus including the common Acorn-shells which live in 



abundance on the rocks of the sea-coast. 

 BATRACHIANS. A class of animals allied to the Reptiles, but undergoing a 



peculiar metamorphosis, in which the young animal is generally aquatic and 



breathes by gills. (Examples, Frogs, Toads, and Xewits.) 

 BOULDERS. Large transported blocks of stone generally embedded in clays or 



gravels. 

 BRACHIOPODA. A class of marine Mollusca, or soft-bodied animals, furnished 



with a bivalve shell, attached to submarine objects by a stalk which passes 



through an aperture in one of the valves, and furnished with fringed arms, 



by the action of which food is carried to the mouth. 

 BRANCHLB. Gills or organs for respiration in water. 

 BRANCHIAL. Pertaining to gills or branchiae. 



CAMBRIAN SYSTEM. A series of very ancient Palaeozoic rocks, between the 

 Laurentian and the Silurian. Until recently these were regarded as the 

 oldest fossiliferous rocks. 



CAXIDJE. The Dog-family, including the Dog, Wolf, Fox, Jackal, &c. 



CARAPACE. The shell enveloping the anterior part of the body in Crustaceans 

 generally ; applied also to the hard shellv pieces of the Cirripedes. 



CARBONIFEROUS. This term is applied to the great formation which includes, 

 among other rocks, the coal-measures. It belongs to the oldest, or Palaeo- 

 zoic, system of formations. 



CAUDAL. Of or belonging to the tail. 



CEPHALOPODS. The highest class of the Mollusca, or soft-bodied animals, 

 characterised by having the mouth surrounded by a greater or less number 

 of fleshy arms or tentacles, which, in most living species, are furnished with 

 sucking-cups. (Examples, Cuttle-fish, Nautilus.) 



CETACEA. An order of Mammalia, including the "Whales, Dolphins, &c., 

 having the form of the body fish-like, the skin naked, and only the fore- 

 limbs developed. 



CHELONIA. An order of Reptiles including the Turtles, Tortoises, &c. 



CIRRIPEDES. An order of Crustaceans including the Barnacles and Acorn- 

 shells. Their young resemble those of many other Crustaceans in form ; 

 but when mature they are always attached to other objects, either directly 

 or by means of a stalk, and their bodies are enclosed by a calcareous shefl 



