362 APPENDIX III 



ALVEOLUS (L. a small cavity) a small cavity or pocket, as the socket of a 

 tooth, or the air pocket of the lung. Plural, alveoli; adjective, 

 alveolar. 



Amblystoma (G. amhlys, blunt plus stoma, mouth) a genus of urodele 

 amphibians; an important form in experimental anatomy. 



Amia (G. amia, a variety of tuna fish) a genus of the Holostei; a fish 

 more resembling the teleosts than other genera of the order. The 

 name is a misapplication of terms. 



Ammocetes (G. ammo, sand, plus coetes, sunk in) the larval stage of 

 the lamprey (a cyclostome) formerly thought to belong to a different 

 family. 



AMNION (G. amnion, a foetal membrane) a membrane enclosing the em- 

 bryo in the reptiles, birds and mammals. 



Amniota, or AMNioTES (see amnion) a group of the vertebrates which in- 

 cludes those which develop an amnion and allantois. 



Amniotic fluid, the fluid secreted by the embryo which fills the amni- 

 otic cavity. 



Amphibia (G. amphi, double, plus hios, life) a class of vertebrates which 

 hatch as gill-breathing larvae, and usually metamorphose into lung 

 breathing adults. 



AMPHicoELous (G. amphi, plus koilos, hollow) a structure concave at 

 both ends, applied to vertebrae. 



Amphioxus (G. amphi, plus oxys, sharp) a vertebrate-like lower chor- 

 date, of the Sub-phylum Cephalochordata. 



amphiplatyan (G. amphi, plus platys, flat) flat on both ends, applied 

 to vertebrae; the mammalian type. 



Amphiuma (G. amphi, plus pneuma, breath) a genus of urodele am- 

 phibia with rudimentary legs, and retaining gill slits. 



ampulla (L. a flask) a bladder-shaped enlargement, as the ampullae of 

 the semicircular canals. 



analogous (G. ana, according to, plus logos, proportion) similar in func- 

 tion, but not necessarily alike in genetic relationship; opposed to 

 homologous. Two structures may be analogous, homologous, or 

 both. The wings of a bird and those of a bat are both analogous 

 and homologous. 



Anamnia (G. an, plus amnion) vertebrates which do not develop an 

 amnion during embryonic development; the cyclostomes, fish, and 

 amphibia. 



anastomosis (G. several openings) a union, or running together, as of 

 two or more veins or other structures. 



ankylosis (G. ankylos, bent) a union or knitting together of two or 

 more bones or parts of bones. 



ANTE (L. before) in front of, anterior. 



ANTHRO (G. anthropos, man), a prefix referring to human; anthropology; 

 Pithecanthropus. 



Anthropoidea (G. anthropos, plus eidos, form), a sub-order of primates 

 including the higher apes and man. 



Anura (G. an, plus oura, tail), an order of tailless amphibia, the frogs 

 and toads. 



anus (L. a ring), the posterior opening of the intestinal canal. 



.\ORTA (G. aeiro, to lift), the large artery leaving the heart. 



Apoda (G. a, plus pons, foot), see Gymnophiona. 



