GLOSSARY. 105 



Pe'taloid (Gr.petalon, a leaf; eidos, shape). A term applied 

 to the ambulacrum of the Echinidea, when it has the ap- 

 pearance of five petals diverging from the apex. 



Pe'tiole (L.petiolus, a stalk). The leafstalk of a plant. 



P etrohy'oid muscle. A muscle which in the frog passes from 

 the hyoid bone to the occipital region of the skull. 



Petro'sal (Gr. petros, a stone). Applied to two sinuses of the 

 dura mater which run along the petrous portion of the 

 temporal bone ; also to branches of the superior maxillary 

 nerve. 



Pg'trous (Gr. petros, a stone). Hard, stony; applied on account 

 of its hardness to the basal part of the temporal bone 

 in which the ear is lodged. 



Pe'trous gan'glion (Gr. petros, a stone). A ganglion connected 

 with the glossopharyngeal nerve, and lodged in a hollow in 

 the petrous part of the temporal bone. 



Peyer's glands. Small ductless glands found in the small intes- 

 tine, so named from the anatomist who first described them. 



Phalan'ges (Gr. phalanx, a line of soldiers). The name given 

 to the bones of the digits, because arranged in rows. 

 (Singular phalanx.} 



Phaneroga'mia (Gr. phaneros, visible; gamos, marriage). A 

 division of plants which includes the exogens and endogens, 

 commonly termed flowering plants. 



Pharyngobran'chii (Gr. pharunx, the throat ; branchia, a gill). 

 An order of fishes containing only Amphioxus, the gills 

 of which consist of a series of clefts in the pharynx. 



Pharyngogna'thi (Gr. pharunx, the throat ; gnathos, a jaw). 

 A group of Teleostean fishes. 



Pharyngo/neu'sta (Gr. pharunx, the throat ; pneuso, I breathe). 

 A division of the Invertebrata comprising the Tunicata 

 and the Enteropneusta, in which the respiratory apparatus 

 consists of a series of branchial clefts in the pharynx. 



Pha/rynx (Gr. pharunx, the throat). The region of the throat 

 behind the nose, mouth, and larynx, and above the 

 oesophagus. 



Pho'cidae (Gr. phoke, a seal). A group of the Pinnipedia which 

 comprises the ordinary seals. 



Phocodon'tia (Gr. phoke, a seal; odous, odontos, a tooth). A 

 group of extinct Cetacea having molar teeth resembling 

 those of the seals. 



Phos'phene (Gr.phos, light; phainomai, I appear). An appear- 

 ance of light produced by pressure on the eyeball. 



