GLOSSARY 



505 



former preying- upon the latter by feeding 

 on its blood, &c., or the food it has dig-ested. 



Parotid glands, the hindermost pair of sali- 

 vary glands. 



Patella (the Latin name), the knee-pan 



Paunch. See Rumen. 



Pearl, in Molluscs, a disease product, formed 

 by deposit of calcareous layers round a 

 foreign body, e.g. a dead parasite or a grain 

 of sand. See also Ground-Pearl. 



Pecten (L. for a comb), a vascular folded 

 structure that projects into the eye of a Bird, 

 behind the lens. 



Pectines (L. for combs), in Scorpions, a pair 

 of comb-shaped organs situated immediately 

 behind the operculum (which see). 



Pectoral (L. pectus, pectoris, the chest), ap- 

 plied to structures, e.g. the fore-limbs of a 

 dog", connected with the chest or thorax. 



Pectoralis major, the great muscle of the 

 breast, by which the fore-limbs are drawn 

 towards one another. 



Pedicellaria, pi. -ae (dim. of L. pedica, a 

 trap), in Star-Fishes and Sea-Urchins, a 

 pincer-like spine. 



Pedipalp, in Spider-like animals (Arachnida), 

 one of the second pair of head-limbs. 



Pelagic (Gk. pelagiktis, marine), living- in the 

 open sea, at or near the surface. 



Pelagic zone, the surface waters of the sea. 



Pelvic, applied to structures, e.g. the hinder 

 pair of fins in a shark, connected with the 

 Pelvis (which see). 



Pelvis (L. pelvis, a basin), applied to that part 

 of the skeleton to which the hind-limbs are 

 attached. 



Pemmican, sun-dried meat. 



Pentadactyle (Gk. pentf, five; daktylos, a 

 fing-er or toe), possessing- five digits. 



Pepsin, an albumen -digesting- ferment con- 

 tained in gastric juice. 



Peptic glands. See Gastric glands. 



Peptone, a soluble and diffusible form of 

 albuminoid. It is produced by the action 

 of g-astric juice and pancreatic juice upon 

 the albuminous part of the food. 



Pericardial, relating- to the pericardium. 



Pericardium (Gk. peri, around; cardia, the 

 heart), the cavity in which the heart is con- 

 tained. 



Peristaltic (the Greek word), applied to the 

 wave-like contractions of the intestines and 

 (in lower forms) blood-vessels. 



Permanent dentition, the second set of teeth 

 in a Mammal. 



Persistent type, an animal species or g-enus 

 persisting for a long- period of g-eolog-ical 

 time, without obvious modification. 



Petal (Gk. pVtaltin, a flower-leaf), one of the 

 inner set (corolla) of investing- flower-leaves. 



Phagocyte (Gk. phagein, to eat; cyttis, a 

 small box, hence a cell), a colourless cor- 

 puscle. 



Phalanges, sing-. Phalanx (Gk. phalanx, a 



fing-er- or toe-bone), bones of fing-ers and 

 toes. 



Pharyngeal, relating- to the Pharynx (which 

 see). 



Pharynx (the Greek name), that region of the 

 digestive tube which follows the mouth- 

 cavity. 



Phylogeny (Gk. phyltin, a tribe; gVnnao, I 

 produce), the evolutionary history of animals. 



Phylum, -a (Gk. phyltin, a race or tribe), one 

 of the main subdivisions of the animal king- 

 dom, e.g. Vertebrata, Mollusca, Protozoa. 



Physiological selection, the theory that the 

 isolation necessary for the origin of new 

 species is due to partial or complete sterility 

 of varying forms with the parent stock. 



Physiology (Gk. physis, nature; Itigtis, a dis- 

 course), the study of the uses or functions 

 of the parts (organs) of plants and animals. 

 It was formerly used in a much wider sense. 



Pilidium, pi. -a (Gk. piliditin, a little cap), in 

 some Nemertine worms, a ciliated larva 

 resembling a cap or helmet with rounded 

 side-flaps. 



Pineal body, a problematic structure con- 

 nected with the roof of the brain in Verte- 

 brates, and probably representing the re- 

 mains of a Pineal eye (which see). 



Pineal eye, an unpaired dorsal eye present in 

 some Reptiles. See Pineal body. 



Pinna, the ear-flap of a Mammal. 



Pinnule (dim. of L. pinna, a feather), in 

 Feather-stars, one of the small branches of 

 the ten arms. 



Pisciculture (L. piscis, a fish), the artificial 

 culture of Fishes, e.g. carp in ponds. 



Pisiform bone (L. pisum, a pea), a small 

 rounded bone present in the carpus of some 

 animals, external to the ulnare (which see). 



Pistil (L. pistillum, pestle), the central part 

 of a flower, in which seeds are produced. 



Pituitary body, a problematic structure 

 attached to the under side of the brain in a 

 Vertebrate. Possibly the vestige of a sense 

 organ (cp. Pineal body). 



Placoid (Gk. plakous, a cake; eidb"s, appear- 

 ance), used of the thick rounded bony scales 

 of Sharks and Rays. 



Placula (Gk. dim. of plakous, a flat cake), a 

 plate-shaped Blastula (which see). 



Plankton (Gk. planktos, wandering), the float- 

 ing and drifting population of the sea and 

 lakes. 



Plantigrade (L. planta, the sole of the foot; 

 gradior, I walk), walking upon the palms of 

 the hands and soles of the feet. 



Planula (L. dim. of planus, a vagrant), in 

 Sponges and Zoophytes, an ovoid ciliated 

 larva. 



Plasma (Gk. plasma, that which has been 

 formed), the fluid part of the blood and 

 lymph. See also Corpuscles. 



Plastron, (Fr. for a breastplate), the under 

 part of the exoskeleton in a Tortoise or 

 Turtle. 



