A GLOSSARY OF TECHNICAL TERMS USED 

 IN THE SYNOPTIC KEY 



(In part after ShuU) 

 Aboral: The region or side of an animal away from the mouth. 



Adductor muscle: The muscle of a bivalve mollusc which serves to 

 close the shell. 



Adoral: The region around the mouth. 



Alimentary canal: The digestive tract of an animal. 



Ameboid: Having the power of changing shape by sending out 

 finger-like processes called pseudopodia. 



Antennae: Jointed appendages which project from the head of an 

 insect or crustacean. 



Anus: The posterior opening of the alimentary tract. 



Ascon type: A type of sponge structure in which the collar cells are 

 located on the wall of the single central cavity. 



Axial filaments: A supporting element running along the axis of 

 a given structure. 



Bilateral symmetry: An arrangement of the parts of an animal 

 such that the opposite sides are mirror images of each other. 



Biramous appendage: An appendage with a basal portion from 

 which two extensions arise. The inner is called the endopod 

 and the outer, the exopod. 



Buccal: Pertaining to the mouth. 



Byssus: A threadlike structure, which is found as an organ of 

 attachment in certain bivalve molluscs and as a sensory 

 organ in certain of their larvae. 



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