684 



COLLEGE ZOOLOGY 



but when multicellular, showing no special- 

 ization of somatic cells. 



Prox'i-mal (L. proximus, next). Nearer the 

 point of attachment of an organ; for exam- 

 ple, the shoulder is at the proximal end of 

 the arm. Opposite of distal. 



Pseu'do-coel (Gr. pseudo, false; koilia, body 

 cavit}). A body cavit\", such as that of the 

 ascaris, not completely lined with a mem- 

 brane derived from mesoderm. 



Pseu'do-po"di-a (Gr. pseudo, false; pous, foot). 

 The blunt temporary protoplasmic projec- 

 tions which are pushed out from an amoeba 

 or amoebalike cell in feeding and locomotor 

 activities. 



Pty'a-lin (Gr. ptyalon, spittle). An enzyme of 

 the saliva in some vertebrates which acts 

 on starch. 



Pul'mo-nar-y (L. pulmo, lung). Pertaining to 

 the lung. 



Py-lor'ic (Gr. pylorus, gate). Pertaining to the 

 pylorus. 



Py-lor'ic cae'ca (Gr. pylorus, gate; L. caecus, 

 blind gut). Digestive glands. 



Py-lor'ic valve (Gr. pylorus, gate; L. valva, 

 folding door). Valve at the posterior end of 

 the stomach. 



Py-re'noid (Gr. pyren, fruit; eidos, form). In 

 some chloroplasts, a center for the formation 

 of a starchlike substance called paramvlum. 



Pyr'i-fof'mis (L. pirum, a pear; ferire, to strike, 

 hew). A muscle arising from the urost}le in 

 the frog. 



Quad-ra'to-ju"gal (L. quadratus, square; jugum, 

 yoke). Posterior bone of the upper jaw in 

 some vertebrates. 



Quad'ru-ped (L. quattuor, four; pes, foot). 

 Four-footed animal. 



Queen. The reproductive female of social in- 

 sects as bees and ants. 



Ra'di-al ca-naF (L. radius, ray. L. canalis, chan- 

 nel). A canal radiating from the disk of 

 starfishes and related animals. Also certain 

 canals in jelhfishes. 



Ra'di-al s}-m'me-try (L. radius, canal. Gr. sym- 

 metria, symmetry). The condition in which 

 similar parts are arranged about a common 

 center like the spokes of a wheel. 



Ra'di-o-ge-nef'ics (L. radius, ray; Gr. gignes- 

 thai, to be born). The study of the effects 

 of radiation upon heredit}-. 



Ra'di-o-ul'na (L. radius, ray; ulna, elbow). 

 The fused radius and ulna bones as in frogs 

 and toads. 



Ra'di-us (L., ray). The bone of the lower 

 arm, located on the thumb side of verte- 

 brates. 



Ra'mus (L., branch). A branch or branching 

 part. 



Re'ca-pit-u-la"tion the'o-ry (L. re, again; caput, 

 head. Gr. theoria, a beholding). The theory 

 that the individual in its development passes 

 through the ancestral histor\' of the race. 

 Ontogeny repeats phvlogeny, 



Re-cep'tor (L. receptor, receiver). A sensory 

 end organ. 



Re-ces'sive trait ( char'ac-ter ) (L. recessus, to 

 withdraw. L. tractus, a drawing. Gr. from 

 charassein, to engrave). A trait which ap- 

 pears onlv when both members of an allelic 

 pair of genes are alike, that is, in the homo- 

 zygous condition. Compare with Dominant 

 trait. The term recessive is also applied to 

 genes. 



Rec'tum (L. rectus, straight). The terminal 

 portion of the large intestine in vertebrates; 

 posterior intestinal region in some higher 

 invertebrates. 



Re'di-a (Redi, the Italian scientist). One of 

 several types of lar\ae found in the life cycle 

 of most trematodes. 



Rc-duc'tion di-vi'sion (L. reducere, to lead 

 back. Diviso, from dividere, to divide). The 

 maturation division in which the homologous 

 pairs of chromosomes are separated to form 

 daughter cells; in this division the paternal 

 and maternal chromosomes of a given 

 homologous pair are separated so that they 

 go to different daughter cells. 



Re'flex act (L. reflexiis, bent back; actum, 

 deed). A relatively simple, automatic re- 

 sponse to a stimulus which is independent of 

 the higher ner\e centers of the brain. 



Re-gen'er-a"tion (L. re, again; generare, to 

 beget). Replacement by growth of a part of 

 the body that has been lost. 



Re'nal ( L. renes, kidneys ) . Pertaining to the 

 kidney. 



Ren'nin (A.S. gerinnan, to curdle, coagulate). 

 A stomach enzyme which acts on casein, a 

 protein of milk. It causes milk to curdle. 



Re'pro-duc"tion (L. re, again; pro, forth; 

 ducere, to lead). Tlie production by an or- 

 ganism of others of its kind. 



