380 GLOSSARY. 



Setaceous. (Lat. seta, a bristle.) Bristle-like. 



Sertrilarida. An order of Hydrozoa. 



Siphonostomata. A division of Gasteropods. 



Sirenia. An order of Mammalia. 



Spicula. (Lat. spiculum^ a point.) Applied to the pointed bodies 

 found in sponges. 



Spiracle. (Lat. spiro, to breathe.) The lateral breathing pores of 

 insects. 



Stigmata. (Gr. o-rty/to, a mark.) A synonym of spiracle. 



Stomapoda. An order of Crustacea. 



Taeniadae. (Lat. tcenia, a tape.) The tape-worms. 



Teleostei. An order of fishes. 



Telson. (Gr. ri\aov, from reAos, end.) The rudimentary terminal 

 segment of the abdomen of arthropods. 



Tergum. (Lat. back.) The dorsal region of crabs and insects. 



Tetrabranchiata. (Gr. rerpas, four ; /3/jayx to > gills*) An order of 

 Cephalopoda. 



Test. (Lat. testa, a shell.) Applied to the calcareous covering of 

 tunicates. 



Thorax. (Gr. 0cfya, a breastplate.) The chest of vertebrates, the 

 middle portion of insects, etc. 



Thysanura. (Gr. Bvffavoi, fringes ; ovpa, tail.) An order of insects. 



Trachea. (Gr. rpaxf'ta, the rough windpipe.) The tube which con- 

 nects the lungs with the mouth. 



Trematoda. (Gr. rp^a, a pore or hole.) An order of worms. 



Trichina. One of the nematoid worms. 



Trichocephalus. One of the nematoid worms. 



Trichoptera. An order of insects. 



Trilobita. An extinct order of Crustacea. 



Truncated. Cut squarely off. 



Tuberculose. Covered with tubercles. 



Tunicata. (Lat. tunica, a cloak.) The primitive vertebrates. 



Turbellaria. (Lat. turbo, I disturb.) An order of worms. 



Umbo. (Lat., the boss of a shield.) The back of a bivalve shell. 



Ungulata. (Lat. tingula, a hoof.) The hoofed animals. 



Univalve. (Lat. unus, one ; valvtz, folding-doors.) A shell com- 

 posed of a single piece. 



Urodela. (Gr. oipa, tail ; Sij\os, visible.) An order of Batrachians. 



Vacuole. (Lat. vacuus, empty.) Cavities in the bodies of Protozoans. 



Ventral. (Lat. venter, the stomach.) Belonging to the lower surface 

 of the body. 



Ventricle. One of the cavities of the heart. 



