362 GLOSSARY. 
Feet (Lat. pedunculus, a stem). Supported upon a stem or 
stalk. 
PELVIS (Lat. basin). The bony arch with which the lower or posterior 
pair of limbs is connected in many Vertebrata. 
PERENNIBRANCHIATA (Lat. perennis, perpetual ; Gr. bragchia, gills). Ap- 
plied to those Amphibia which retain their gills throughout life. 
PERISSODACTYLA (Gr. perissos, uneven; daktulos, finger). Applied to 
those Hoofed Mammals (Ungulata) which have an uneven number of 
toes. 
PERIVISCERAL (Gr. peri, around; Lat. viscera, the internal organs). Ap- 
plied to the space surrounding the viscera in most animals. 
PHALANGES (Gr. phalanx, arow). The small bones composing the digits 
of the higher Vertebrates. Normally each digit has three phalanges. 
PHARYNGOBRANCHII (Gr. pharuga, the pharynx ;, bragchia, gills). The 
order of Fishes comprising only the Lancelet. 
PHARYNX. The upper part of the gullet. 
PHYLLOPODA (Gr. phullon, leaf ; podes, feet). An order of Crustacea. 
PHYSOPHORIDA (Gr. phusa, bellows: or air-bladder ; phevo, I carry). An 
order of Oceanic Hydrozoa. 
PInNz (Lat. pinna, a feather). Lateral processes, applied especially to 
the processes of the arms of Crinoids, or of the tentacles of Alcyonaria. 
PINNIGRADA (Lat. pinna; and gradior, I walk). The family of Carnivora, 
comprising the Seals and Walruses,. adapted for an aquatic life. 
Fees (Lat. piscis, a fish). The class of the Vertebrata comprising the 
fishes. 
PLACENTA (Lat. a cake), The ‘‘after-birth,” or the organ by which a 
vascular connection is established in the higher Vertebrata between the 
mother and the young animal previous to its birth. 
PLACENTAL. Possessing a placenta, or connected with the placenta. 
PLACOID (Gr. plax; a plate; etdos, form). Applied to the irregular bony 
plates, grains, or spines which are found in the skin of various fishes. 
PLAGIOSTOMI (Gr. plagios, transverse; stoma, mouth). The Sharks and 
Rays, in which themouth is transverse, and is placed on the: under sur- 
face of the head. 
PLANARIDA (Gr. plané, wandering). A group of the Scolecida.. 
PLANTIGRADA (Lat. planta, the sole of the foot ; gradior, I walk), The 
group an the Carnivora in which the sole of the foot is applied to the 
ground, 
PLANTIGRADE. Walking upon the soles of the feet. 
PLASTRON (Gr. emplastron, a plaster). The ventral shield of the case of 
the Tortoises and Turtles (Chelonia). 
PLATYRHINA (Gr. platus, broad; rhines, nostrils). A group of the Quad- 
rumana. 
PLESIOSAURIA (Gr. plesios, near; saura, a lizard), An extinct order of 
Reptiles. 
PuuTevs (Lat. ashed). The larval form of the Sea-urchins (Zchinus). 
PNEUMATIC (Gr. pnewma, air). Filled with air. 
PNEUMATOPHORE (Gr. pneuma, air; phero, I carry). The air-bladder of 
the Physophoride. 
PoposomMatTa (Gr. pous, foot ; soma, body). An order of Arachnida. 
PoIsERS. See Balancers. 
Po.LuEx (Lat. the thumb). The innermost of the normal five digits of the 
fore-foot of the higher Vertebrata. The thumb of man. 
PonycystTiIna (Gr. polus, many ; kustis,a bladder). An order of Protozoa. 
POLYGAMOUS (Gr. polus, many; gamos, marriage). Applied to cases in 
which one male consorts with several females. 
POLYGASTRICA (Gr. polus, many; gaster, stomach). The name applied by 
