G L O S S A R Y.' 



ABDOMEN (Lat.). The posterior cavity of the body, 

 separated from the chest by the diaphragm, and con- 

 taining the intestines, liver, kidneys, and other viscera. 



ABOMASUM (Lat. ab, from, and omasum, bullock's 

 tripe). The fourth or true digestive stomach in the 

 compound stomach of the ruminants. Also called Rennet 

 Stomach. See fig. 37. 



ACCESSORY HOOFS. See Hooks. 



ACETABULUM (Lat., a cup-shaped vessel). The 

 socket in which the upper end of the thigh-bone is 

 inserted. In the Echidna or spiny ant-eater this socket 

 is not ossified in the middle, so that the part of the pelvis 

 where it is situated appears perforated in the dry skeleton, 

 as in birds, &c. 



ALLANTOIS (Gr. alias, allantos, a sausage). A pear- 

 shaped sac developed from the posterior end of the primi- 

 tive alimentary canal in the young of mammals and some 

 other vertebrates before birth. In the higher mammals 

 it elongates, and while the terminal portion expands and 

 enters into intimate connection with the wall of the 

 uterus in the parent, and thus helps to form the placenta, 

 the other portion forms part of the umbilical cord, con- 

 taining the great blood-vessels by means of which the 

 vascular system of the young is brought into communica- 

 tion with that of the parent. After birth the portion of 

 the allantois within the body of the young remains through 

 life as the urinary bladder. 



ALLUVIAL. Belonging or pertaining to alluvium. 



ALLUVIUM (Lat. alluvio, an inundation). A deposit 

 of soil collected by the action of water; a term sometimes 

 specifically applied in geology to the more recent of the 

 Post-tertiary or Quaternary deposits, those in which the 

 mammals are all of still living species. In this sense, in 

 which it is distinguished from Diluvium, the word is 

 more frequently used by continental than by English 

 writers. 



AMNION (Gr.). A membrane investing the young 

 of mammals and some other vertebrates before birth. 



AMPHIBIA (Gr. amphi, both, and bios, life). A 

 class of vertebrates adapted in the young condition to 

 live in the water and breathe by gills, but in a more 

 advanced stage to live on land and breathe by lungs. 



ANAL (Lat. anus, the posterior or inferior opening 

 of the alimentary canal). Pertaining to, or situated in 

 the neighbourhood of the anus; as, rt;/a/ glands. 



ANALOGOUS (Gr. ana, according to, and logos, 

 ratio). A term applied in natural history to mean similar 



'The author is indebted to Prof. W. A. Herdman of University 

 College, Liverpool, for kindly reading the proofs of this Glossary. 



in function though different in structure, as the wing of a 

 bird and the wing of a bat. See Ho.mologols. 



AN.\S rOMOSE (Gr. ana, again, anew, and stoma, a 

 mouth). To inosculate with or run into each other; to 

 communicate with each other, as the arteries and veins. 



ANCESTOR (Old Fr. anccstre, from Lat. antecessor, 

 a predecessor). In the language of the evolutionary 

 theory a form from which a later form is believed to have 

 developed by natural descent. 



ANCESTRAL. Pertaining to an ancestor; having 

 the character or characters of an ancestor in the evolu- 

 tionary sense of that term. 



ANKYLOSED, or Anchvlosed (Gr. angkylos, crooked, 

 angkyle, a joint). A term applied to bones immovably 

 fi-^ced together in jjlaces where joints have at one time 

 existed or usually do exist. 



ANTHROPOID (Gr. anthnpos, man, eitlos, form). 

 Resembling man. 



ANTHROPOMORPH^ (Gr. anthrdpos, a man, and 

 morplie, form). The name of the group of apes which 

 has most resemblance to man; the group including the 

 gorilla and chimpanzee, the orang-utang, and the gibbons. 



ANTHROPOMORPHOID. Belonging to or resem- 

 bling the Anthropomorphae. 



ANTLERS. The branching horns of a stag. See 

 fis. I. 



Fig. I— ."Vntlersof Red Deer. ir. Brow-tine; btz. Bez-tine ; a.r. Antkr-royal ; 

 s.r. Sur- royal. 



APOPHYSIS (Gr. apo, from, and physis, growth). 

 A protuberance growing out from a bone; a knob or 

 prominent part of a bone, whatever shape it may happen 

 to possess. 



ARBOREAL (Lat. arbor, a tree). Living on or fre- 

 quenting trees. 



ARCHAIC (Gr. arc/ti, beginning). Primitive; . as 

 applied to structures in an evolutionary sense, belonging 

 to a primitive type. 



