6o SYNOPTIC KEY 



Spores: Small particles of protoplasm which become surrounded 

 with a resistant covering and so are able to withstand extreme 

 conditions. 



Statoblast: A gemmule-like body by means of which many Bryozoa 

 reproduce asexually. 



Sycon type: A type of sponge structure in which the central 

 cavity is free from collar cells which are located in side 

 branches from this cavity. 



Symmetrical: Of a form that may be divided' by a line or plane 

 into two parts that are mirror images of each other. 



Tarsus: The distal part of th^ foot of an insect; it is normally 

 composed of more than one segment. 



Tentacle: An elongated tactile organ. 



Terrestrial: Pertaining to land; animals that live on land. 



Thorax: A middle portion of the body of many animals, between 

 the head and abdomen. 



Trachea: An air tube, normally stiffened by rings of supporting 

 tissue. 



Tracheal gills: Arrangements whereby the tracheal vessels are 

 brought near the water for purposes of respiration (in aquatic 

 insects). 



Tubercle: A rounded swelling. 



Umbrella: The jelly-like body of the medusa resembles an umbrella 

 with the manubrium in the place of a broken handle. 



Velum: A shelf of muscular material placed near the edge of the 

 bell of a jellyfish much as a running track is placed around 

 a gymnasium. 



Ventral: Literally, pertaining to the belly, hence usually the lower 

 part of an animal. 



Zooecium: The body wall of a bryozoan. 



