GLOSSARY 



OF ANATOHnCAL AND OTHER SCIENTIFIC TERMS USED IN THESE 

 LECTURES. 



Abdomen. (Lat. abdo, I conceal.) The posterior and principal cavity containing 



the bowels and many other viscera of the animal. The abdomen is distinct from 



the thorax in crustaceans, spiders, and insects. 

 Abdominales. (Lat. abdomen.) An order of fishes, so called from the attachment 



of the ventral fins to the abdomen behind the pectorals. 

 Aberrant. (Lat. aberro, I wander from.) This term is applied to those species 



which deviate most froin the type of their natural group. 

 Abranchiate. (Gr. a, without; bragchia, gills.) When an animal is devoid of 



gills. 

 AcALEPHA. (Gr. akalephe, a nettle.) The class of radiated animals with soft 



skins, which have the property of stinging like a nettle. 

 AcANTHOCEPHALA. ( Gr. aJtajtthos, a spine ; kephale, a head. ) The order of intes- 

 tinal worms having the head armed with spines or hooks. 

 AcARUS. ( Gr. akari, a mite. ) The name of a genus of Arachnida, to which the 



cheese-mite and allied species belong. 

 Acaridje. The family of which the genus Acarus is the type. 



AcASTA. (Gr. akaste.) A name arbitrarily applied to a genus of Barnacles, para- 

 sitic upon sponges. 

 Acephalous. ( Gr. a, without ; kephale, hea.A.) Headless. The animals in which 



a distinct head is never developed. 

 AcEPHALOCYST. The parasitic hydatid, which consists of a cyst or bag without a 



head. 

 AcETABULA. (Lat. acetabulum, a shallow cup.) The fleshy sucking-cups with 



which many of the invertebrate animals are provided. 

 Acini. (Lat. acinum, a berry.) The secerning parts of glands, when they are 



suspended like grains or small berries to a slender stem. 

 Acoustic. (Gr. akouo, I hear.) Appertaining to sound, or the organ of hearing. 

 Acrita. (Gr. ahritos, confused.) A term applied to the lowest animals, in which 



the organs, and especially the nervous system, were supposed to be confusedly 



blended with the other tissues. 

 Actinia. (Gr. aktin, a ray.) The genus of Polypes, which have many arms 



radiating from around the mouth. 

 Actinoceros. ( Gr. aktin, st rny ; ieras, a horn.) A generic term, signifying the 



radiated disposition of the horns or feelers. 

 Adipose. ( Lat. adeps, fat. ) Fatty. 

 Akkra. (Gr. a, without; Aeras, a horn. ) The family of Mollusca, without horns 



or feelers. 

 Alar. (Lat. ala, a wing.) Belonging to a wing. 



Albuminous. (Lat. albumen, white of egg. ) Consisting of albumen, or the sub- 

 stance which forms the white of an egg. 

 Aliform. Shaped like a wing. 

 Alula. A little wing. 

 Ambulacra. (Lat. ambulacrum, an avenue or place for walking.) The perforated 



series of plates in the shell of the sea-star or sea-urchin. 

 Ambulatory. (Lat. amhulo, I walk.) An animal or a limb made for walking. 

 Ammonites. An extinct genus of Mollusca, allied to the Nautilus, which inhabited 



a chambered shell, called Ammonite from its resemblance to the horns on the statues 



of Jupiter Ammon. 

 Amorphous. (Gr. a, without; morphe, form.) Bodies devoid of regular form. 

 Amphipods. (Gr. amphi, on both sides; pons, a foot.) The order of Crustacea, 



which have feet for both walking and swimming. 



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