326 
OL0S8ABT. 
Thy-san-u'ra (Gr. thusanoi, 
fringes; oura, tail). The low- 
est order of insects. 
To-men-tose'. Covered with fine 
matted Imirs. 
Tra-bec'u-l^ (cranii), dim. of 
tmbs, a beam. Applied to the 
longitudinal cartilaginous bars 
of the fore- part of the head of 
vertebrate embryos. 
Tra'che-a (Gr. tracheia, the 
rough windpipe). The respira- 
tory tube in vertebrates; the 
air-tube of tracheate insects. 
Trem-a-to'da (Gr. trema, a pore 
or hole). An order of worms. 
Trun ca'ted. Cut squarely off ; 
docked. 
Tu-ber'cu-lose. Covered with 
tubercles. 
TuN-i-CA'TA(Lat. tunica, ^Q\o2ik). 
The class of chordata called 
Ascidians. 
Um'bo (Lat. the boss of a shield). 
The beak of a Lamellibranchi- 
ate shell. 
Un-gu-la'ta (Lat.ungula, a hoof). 
The order of hoofed mammals. 
U-ro-de'la (Gr. oura, tail; delos, 
visible). The tailed Batrachi- 
ans. 
U-ro-mere' (Gr. ^>?^r^?s, tail ; mei os, 
a part). Any of the abdominal 
segments of an Arthropod. 
U-ROP'o-DA (Gr. our OS ; pous, po- 
dos, foot). Any of the abdom- 
inal feet of Arthropoda. 
U-ro-some' (Gr. ouros, VaM^meros, 
a part). The abdomen of Ar- 
thropods. 
U-RO- STERN 'iTE. The Sternal or 
under piece of the uromeres or 
abdominal segments of insects. 
Yac-u-ole' (Lat. vacuus, empty). 
The little cavities in the bodies 
of Protozoa. 
Vein. Applied to the ribs or 
nervures" of the wings of in- 
sects; the branches of the veins 
are called venules. 
Yen'tiial. Applied to the under 
side of the abdomen, or of the 
body of invertebrates. 
Yen'tri CLE (Lat. ventriculus, di- 
minutive of veil ter). One of the 
cavities of the heart or brain- 
Yer ric'u-late. With thick set 
tufts of parallel hairs. 
Yer'ru-cose. Covered with wart- 
like prominences. 
Yer'te-bra (Lat. verto, I turn). 
One of the bones of the spinal 
column or backbone. 
Yer-ti-cil'late. Placed in 
whirls. 
Yes'i-cle (Lat. vesica, a blad- 
der). A little sac, bladder, or 
cyst. 
Yis'cE-RA (Lat. viscus). The in- 
ternal organs of the body. 
Yi-vip'a-rous (Lat. vivus, alive; 
and pario, I bring forth). Ap- 
plied to animals which bring 
forth their young alive. 
Zo'oiD (Gr. zoon, animal; eidos, 
form). The highly specialized 
organs of such animals as the 
Hydroids, and other compound 
forms which have a marked in- 
dividuality, and which might 
be mistaken for genuine indi- 
viduals. 
Zo-o'PHYTE (Gr, zoon, animal; 
phuton, plant). Applied to the 
plant-like polyps, sertularians, 
and sponges. 
