Index and Glossary. 



morphological units of the body of 

 a jointed animal, 13 



Segmental organs, excretory tubes 

 in the segments of worms, 58 



Serpula, 72 



Sertnlaria, 34 



Shell, oo 



Silica, flint. 



Silkworms, 130 



Siphon, 84 



Siphonophora, 38 



Siphuncle, 90 



Snail, 87 



Solen, the razor-shell, 84 



Specialisation, setting apaw of an 

 organ for a special function, and 

 for it alone, 13 



Species, a group of identical indi- 

 viduals under a common name, n 



Spicules, siliceous or calcareous 

 masses embedded in animal tissues, 

 31 



Spiders, no 



Spinnerets, in 



Spirorbis, 72 



Sponges, 29 



Spongilla, a freshwater sponge, 31 



Spoon-worms, 67 



Star-fishes, 7, 47 



Stellerida, 50 



Stipes, part of an insect's head, 117 



Stock, the common sfcm of a colony. 



Strepsiptera, a small order of in- 

 sects, 127 



Strongylocentrotus, a common sea- 

 urchin, 32 (fig.) 



Symmetry, 8 



T JEN I A, the tapeworm, 60 

 Tarsus, the last joints of an 



insect's leg, 115 

 Teeth of sea urchin, 54 

 Tegenaria, the house spider, in 

 Telspn, the middle flap of a lobster's 



tail, loi 



Tenebrio, the meal-worm, 132 

 Tentacles, feelers, 32, 33 

 Terebratula, 80 

 Termites, 126 



Test, a shell or exoskeleton, 

 Thalassicolla, sea-glue, a group of 



marine protozoa, 25 

 Thorax, the chest, or the region of 



the body of an insect which bears 



the legs, 1 16 



VOR 



Thread-cells, stinging cells of jelly- 

 fishes. 33 



Thrips, 125 



Thysanoptera, an order of insects, 

 125 



Thysanura, 124 



Tibia, part of an insect's leg, 115 



Ticks, no 



Trachea;, air-tubes for breathing, 



TraXeal 3 ' 



lungs, groups of tracheae 



compressed together, no 

 Trematoda, an order of parasitic 



worms, 63 

 Trepang, an edible sea-cucumber, 



56 



Trichina, a parasitic worm, 65 

 Trichocephalus, 65 

 Trichoptera, an order of insects, 127 

 Trilobites, 104 

 Trochal disks, the ciliated lobes on 



the heads of some minute worms, 



79 

 Trochanter, the second joint in the 



leg of an insect, 119 

 Troctes, the death-tick insect, 125 

 Tubipora, the organ-pipe coral, 46 

 Tunicates, 75 

 Tunic, 75 

 Turbellaria, 59 

 Types, ii 



TTNDIFFERENTIATED, not 

 *"' separated into specialised 

 parts. 



WACUOLES, clear spaces in 

 v masses of protoplasm, 20 

 Valves of shells, 80 

 Ventral, the under side of the 



body. 

 Ventricle, the cavity of the heart 



which by its contraction drives on 



the blood in the circulation, 94 

 Venus' Flower Basket, a sponge, 31 

 Vermes, worms, 14, 57 

 Vertebrata, 14 

 Viscera, the digestive and other 



internal organs of the body of 



an animal. 

 Vorticella, 25, 27 



