Glossary. 



Abdomen. Hind division of body. 



Abdoniinal feet. Appendages of the abdomen; many as six pairs may be 



developed. 

 Abyssal. Of the depths, said of deep-sea forms. 



Accessory gill. Additional or extra gill. . 



Acicle. Stout bristle; said of scale of second antenna v/hen not laminar. 

 Adductor muscle. Muscle closing shell and passing transversely from valve 



to Valve, as in many entomostraca. 

 Adhesion pads. Holding disks, as those of many parasitic forms. 

 Aerial. Living in the air. 

 JEsthetask. Sense-clubs, as those on the antennae of certain copepods, like 



Cyclops and Diaptomus. 

 Afferent. Conveying inward. 

 Alee. Wings. 

 Alecithal. Said of eggs when the yolk material is evenly distributed and of 



small quantity. 

 Ambulatory. Walking; as of the legs, which may be many as five pairs. 

 Anal segment. Usually last segment of body. 

 Anchylosed. Grown solidly together. 

 Andricuni. Male organ on first pair of abdominal appendages, as in some 



prawns. 

 Annulns z'entralis. -Plate containing female genital-opening, as in crawfishes. 

 Antenna. Feeler; usually known as the second pair of appendages of the 



head — thus antenn?e, second, outer, or under antennas. 

 Antcnnulc. A little antenna; usually known as the first pair of appendages 



of the head — thus antennules or first antennje. Their divisions often 



comprise the peduncle, flagellum and secondary appendage. 

 Antrorse. Turned forward. 



Anus. Posterior aperture of the alimentary canal. 

 Apodeme. Plates of chitin passing inward from integuments of crustaceans, 



dividing as well as supporting their internal organs. 

 Arcuate. Curved. 

 Areola. Small space between line defining upper extent of gills, as seen on 



upper surface of thorax in crawfishes. 

 Article. Segment. 

 Asexual. Without sex. 

 Asymmetrical. Not symmetrical, or one side or portion developed more than 



the other. 

 Attenuate. Long and slenderly pointed. 



Basipodite. Base-foot, or =cco'nd basal joint of a limli; basis. 

 Biarticulate. Two-jointed. 



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