GLOSSARY. 
.G-soPH'a-Gus (Gr. otsos, a reed ; 
phagein, to eat). The gullet. 
On-T0G'E-Ny (Gr. on, ontos, being; 
gene, birth), The development 
from the egg, of an individual 
animal. 
O-PER'CU-LUM (Lat. operio, to 
cover). In fishes one or more 
bones covering the gills; in 
Gastropod mollusks a horny 
plate or solid limestone mass 
closing the orifice of shells. 
O-Pis-THO-caz'LOUS (Gr. opisthen, 
behind ; Xotlos, hollow). Those 
Per vertebrates with bodies hollow 
“behind and convex in front. 
O'RaL. Related to the mouth. 
OR-NI-THO-DEL'PH I-A (Gr. ornis, 
bird; delphus, womb). The 
sub-class of mammals and or 
der Monotremata. 
OR-THOP’TE-RA (Gr. — orthos, 
straight ; pteron, wing). The 
order of insects with straight 
narrow fore-wings, as the grass- 
hoppers. 
Os-TRA'co-DA (Gr. ostracodes, 
shelled). A group of shelled 
crustacea. 
O'ro-LiTHs (Gr. ous, ear ; lithos, 
stone). Small bones suspended 
in the internal ear of fishes, or 
concretions in the auditory 
sacs of invertebrates. 
O-vip'A-RoUS (Lat. ovum, an egg; 
parto, I bring forth). Applied 
to animals bringing forth eggs 
instead of living, active young. 
O-vi-Pos'I-ToR (Lat. ovwm, an 
egg; pono, I place). An organ 
in insects homologous with the 
sting, by which eggs are de- 
posited in solid substances. 
O’vr-sac. A sac or bag-like mem- 
695 
brane attached to the parent, 
and containing eggs, 
O-vo-vi-vip'a-Rous (Lat. ovwm, 
an egg; vivus, alive; pario, I 
bring forth). Applied to such 
animals as retain their eggs in 
the body until they are hatched. 
Pa po-GEn'E-sis. Parthenoge- 
nous development in larval in- 
sects. 
Pau'tt-uM (Lat. a cloak). The 
mantle or body-wall of mol- 
lusks, which secretes the shell; 
adj. pallial. 
Pa-piu'La, A minute soft projec- 
tion. 
Pa-REN'CHY-MA (Gr. paregchuma, 
from para, en, chuo, something 
poured in besides). Applied 
to the proper substance of vis- 
cera, excluding connective tis- 
sue, blood-vessels, and other 
accessory parts. 
PAR-THE-NO-GEN’E-818 (Gr. par- 
thenos, virgin; genesis, genera- 
tion). Reproduction by direct 
growth of germs from the egg, 
without fertilization by male 
germs or spermatozoa, asin the 
aphis, gall-insects, fluke-worm, 
etc. 
Pet'a-eio. Living on the high 
seas,-away from the coast; in 
mid-ocean. 
Per'i-somE (Gr. peri, around; 
soma, body). In Crinoids the 
oral region of the cup or body. 
PE-REN-NI-BRAN'CHI-A-TA (Lat. 
perennis, perennial: branchia, 
gill). Those Batrachia which re- 
tain their gills throughout life. 
PER-IS-SO-DAC'TY-LA (Gr. perissos, 
uneven; daktulos, finger). 
