310 MANUAL OF ZOOLOGY. 



STREPSIPTERA (G-r. strepho, I twist ; and pteron, wing). An order of Insects, 

 in which the anterior wings are represented by twisted rudiments. 



STROBFLA (Gr. strobilos, a top, or fir-cone). The adult tape-worm with its 

 generative segments or proglottides. Also applied to one of the stages 

 in the life-history of the Lucernarida. 



STYLIFORM (Lat. stylus, a pointed instrument ; forma, form). Pointed in 

 shape. 



SUB-CALCAREOUS. Somewhat calcareous. 



SUB-CEXTRAL. Nearly central, but not quite. 



SUB-PEDUXCULATE. Supported upon a very short stem. 



SUB-SESSILE. Nearly sessile, or without a stalk. 



SUTURE (Lat. suo, I sew). The line of junction of two parts which are im- 

 movably connected together. Applied to the line where the whorls of a 

 univalve shell join one another; also to the lines made upon the exterior 

 of the shell of a chambered Cephalopod by the margins of the septa. 



SWIMMERETS. The limbs of Crustacea, which are adapted for swimming. 



SYXAPTICUL^E (Gr. sunapto, I fasten together). Transverse props sometimes 

 found in Corals, extending across the loculi like the bars of a grate. 



SYSTOLE (Gr. sustello, I contract). Applied to the contraction of any con- 

 tractile cavity, especially the heart. 



TABULA (Lat. tabula, a tablet). Horizontal plates or floors found in some 

 corals, extending across the cavity of the ' theca,' from side to side. - 



TACTILE (Lat. tango, I touch). Connected with the sense of touch. 



TJKXIADA (Gr. tainia, a ribbon.) The division of Scolecida comprising the 

 Tape-worms. 



TJEXIOID (Gr. tainia ; and eidos, form). Ribbon-shaped, like a tape-worm. 



TECTIBRANCHIATA (Lat. tectus, covered; and Gr. bragchia, gills). A divi- 

 sion of Opisthobranchiate Gasteropoda in which the gills are protected 

 by the mantle. 



TEGUMENTARY (Lat. tegumentum, a covering). Connected with the integu- 

 ment or skin. 



TELSOX (Gr. telson, a limit). The last joint in the abdomen of Crustacea; 

 variously regarded as a segment without appendages, or as an azygos 

 appendage. 



TERGUM (Lat. for back). The dorsal arc of the somite of an Arthropod. 



TERRICOLA (Lat. terra, earth ; and colo, I inhabit). Employed occasionally 

 to designate the Earth-worms (Lumbrieidcs). 



TEST (Lat. testa, shell). The shell of Mollusca, which are for this reason 

 sometimes called 'Testacea;' also the calcareous case of Echinoderms ; 

 also the thick leathery outer tunic in the Tunicata. 



TESTACEOUS, provided with a shell or hard covering. 



TESTIS (Lat. testis, the testicle). The organ in the male animal which pro- 

 duces the generative fluid or semen. 



TETRABRANCHIATA (Gr. tetra, four ; and bragchia, gill). The order of Cepha- 

 lopoda, characterised by the possession of four gills. 



THALASSICOLLIDA (Gr. thalassa, sea; and kolla, glue). A division of Pro- 

 tozoa. 



THECA (Gr. theke, a sheath). A sheath or receptacle. 



THECOSOMATA (Gr. theke; and soma, body). A division of Pteropodous Mol- 

 luscs, in which the body is protected by an external shell. 



THREAD-CELLS. (See Cnidse.) 



THYSANURA (Gr. thusanoi, fringes ; and oura, tail). An order of Apterous 

 insects. 



TRACHEAE (Gr. tracheia, the windpipe). The breathing tubes of insects. 



