108 GLOSSARY. 



Platyno'ta (Gr. platunotos, broad-backed). A group of the 



Lacertilia. 

 Platyrrhi'ni (Gr. plains, broad ; rhis, rhinos, the nose). A 



family of the Simiadse having remarkably wide and flat 



noses. 

 Platys'ma myoi'des (Gr. platusma, a plate ; mus, a muscle ; 



eidos, shape). A thin flat muscle of the neck. 

 Plecto'gnathi (Gr. plektos, plaited, twisted ; gnathos, a jaw). 



A group of Teleostean fishes which have the premaxillae, and 



usually the hyomandibular, immovably united with the skull. 

 Plesiosau'ria (Gr. plesios, near ; saurios, a lizard). A group of 



extinct Reptilia. 

 Pleu'ra (Gr. pleura, a rib). The serous membrane which lines 



the thorax and envelopes the lungs. 

 Pleu'ra costa'lis (L. costa, a rib). The layer of the pleura 



which lines the thorax. 

 Pleu'ra pulmona'lis (L. pulmo, pulmonis, a lung). The layer of 



the pleura which invests the lungs. 

 Pleu'ral facet'. The smooth surface on the anterior surface of 



the pleuron of each somite in the Crustacea. 

 Pleu'rodont (Gr. pleuron, a side; odous, odontos, a tooth). 



Applied to the dentition of the Lacertilia, when the teeth 



are ankylosed by their sides to the parapet of the jaw. 

 Pleuronec'tidse (Gr. pleuron, a side ; nektos, swimming). The 



flat fishes ; so called because they swim on their side. 

 Pleuroperitone'al (Gr. pleuron, a side ; peri, around ; teino, I 



stretch). The general cavity of the trunk when undivided 



by a diaphragm. 

 Pleurospondy'lia (Gr. pleuron, a rib; spondulos, a vertebra). 



Applied to the Reptilia in which the ribs are not movable 



upon the vertebrae. 

 Pleuros'teon (Gr. pleuron, a side ; osteon, a bone). The antero- 



lateral piece of the sternum in birds. 

 Plex'us (L. plexus, woven together). The name given to the 



interlacing networks of nerves or nerve-fibres found in 



different parts of the body. 

 Pli'ca guberna'trix (L. governing or guiding fold). An elevated 



fold which projects into the peritoneal pouch of the foetus 



previous to the descent of the testis. 

 Plfca semiluna/ris (L. semilunar fold). A vertical fold of the 



conjunctiva in the inner angle of the human eye. 

 Pli'cse semiluna'res (L. semilunar folds). Two folds of the peri- 

 toneum, behind the bladder. 



