388 INDEX-GLOSSARY. 



83; Anodonta, Unio, 114; Helix, 127; Amphioxus, 141; Seyllium, 

 161; Rana, 194; Columba, 244; Lepus, 288; Comparative, 312. 







Oceanic Is. , 348. 



Occipital (occiput, the back of the head) Belonging to the hinder region 

 of the skull, 179. 



Odontophora, 341. 



Odontophore (6<5ous. oSov-r-, a tooth; (pepw, I bear; 0o/oo?, bearing), in the 

 Snail A rasping structure which projects into the floor of the mouth 

 cavity, 125. 



Odontophoral cartilages, 215. 



Odours, 369. 



(Esophagus. See Gullet. 



Old Calabar, 349. 



Olfactory Organs, 66; Astacus, 103; Anodonta, Unio, 121; Helix, 123, 

 133; Scyllium, 172; Rana, 218; Columba, 255; Lepus, 304; Com- 

 parison of, 320. 



Ommatidium (dim. of o/^ua-r;oi/, a little eye) One of the elements of a com- 

 pound eye, 103, 104. 



Omo-sternum (w/xos, the shoulcter ; crTcpvov, the breast), 184. 



Ontogeny (ov-ra, beings ; yei/j/aco, I produce) The development of indi- 

 viduals, 2. 



Operculum (operculum, a lid, a cover), 36, 225. 



Ob'genesis (wov, an egg; yivwis, birth) The development of the ovum, 52. 



Ob'sperm (u'v ; ov'ippa., seed) The sexual cell produced by fertilization of 

 the ovum, 25, 74. 



Obtheca (a' ; 0jxti, a cover, a case) A female organ for the storage of ova 

 (receptaculum ovorum), 64. 



Opossum, 354. 



Optic thalami The thickened side-walls of the thalamencephalon, 210, 

 252.; 



Orang-outan, 338. 



Orbit, 182, 232, 271, 325. 



Organ, 1. 



Organic acids, 58. 



Oriental Region, 350, 351. 



Origin of species, 5; of muscle The end attached to a relatively fixed 

 part, 91. 



Ornithodelphia, 1345. 



Ornithorhynchus, 345, 353. 



