oi 2 GLOSSARY. 



Oceanic. Applied to animals \vhicli inhabit tlie open ocean. 



OcTOPODA (Gr. octo, eight ; podes, feet). The tribe of Cuttle-fishes with eight 



arms round the hea<i. 

 Odontolc^ (Gr. odous, a tooth ; holkos, a furrow). An order of extinct Birds, 



comprising only the genus Hesperornis, in which the teeth are sunk in a 



deep groove. 

 Odontophore (Gr. odous, a tooth ; pliero, I carry). The so-called "tongue" 



or masticatory apparatus of the Gasteropoda, Pieropoda, Cephalopoda. 

 Odontornithes (Gr. odoiis, tooth ; amis, bird). The extinct sub-class of 



Birds comprising forms with distinct teeth in sockets. 

 ODONTOTORjMiE (Gr. odrn/s, a tooth ; tormos, a socket). An order of extinct 



Birds, comprising Ichthyornis only, in which the teeth are sunk in sockets. 

 CEsoPHAGU^. The gullet, or the tube by which the food is conveyed from the 



mouth to the stomach. 

 Oligoch^ta (Gr. oligos, few; chaite, bristles). An order of the Annelida, 



comprising the Earth-worms. 

 Omasum (Lat. bullock's tripe). The third stomach of Ruminants, commonly 



called the "psalterium." 

 Omnivorous (Lat. omnia, everything; voro, I devour). Feeding indiscrimin- 

 ately upon all kinds of food. 

 Operculum (L-it. a lid). Tlie shelly or horny plate by which the shell of a 



Univalve Mollusc is closed when the animal has retired within it ; also the 



chain of fiat bones which covers the gills in many fishes. 

 Ophidia (Gr. aphis, a serpent). Tlie order of Reptiles comprising the Snakes. 

 Ophiomorpha (Gr. aphis, a serpent ; 7)iorphe, shape). The order of Amphibia 



comprising the Ccrcdirc. 

 Opuiuroidea (Gr. ophis, a serpent ; (nira, tail ; eidos, form). An order of 



Echinodennata comprising the Brittle-stars and Sand-stars. 

 OpiSTHOCtELOUS (Gr. opisihen^ behind; koilos, hoDow). Applied to verte- 

 brae, the bodies of which are hollow or concave behind, and convex in front. 

 Oral (Lat. os, the mouth). Connected with the mouth. 

 Orthoptera (Gr. ortkos, straiglit ; j^^^^on, a wing). An order of Insects. 

 OSCULA (Lat. diminutive of os, mouth). The largo apertures (" exhalaut aper- 

 tures") by which a sponge is peii'orated. 

 OsTRACODA (Gr. ostrakon, a shell ; eidos, form). An ordfV of small Crus- 

 taceans which are enclosed in bivalve shells. 

 Oviparous (Lat. ovum, an egg; pario, I bring forth). Applied to animals 



which bring forth eggs, in contradistinction to those which bring forth their 



young alive. 

 Ovipositor (Lat. ovuvi, an e,crg ; j)ovn, I place). The organ possessed by some 



insects, by means of which tht; cLigs are placed in a position suitable for 



their development. 

 Ovisac The external bag or sac in which certain of the Invertehrata carry 



their eggs after they aie extruded from the body. 

 Oyo-viviFAROUS (Lat. ovvm, an egg; vivus, alive ; ^j«r/o, I bring forth). 



Applieil to animals which retain their eggs within the body until they are 



hatched. 

 Ovum (Lat. an egg). Tlie germ pruduced within the ovary, and capable under 



certain conditions of being developed into a new individual. 



Pachydermata (Gv. pachi's, thick; c?e7''/7ia, skinV An old jMammalian order 

 constituted by Cuvier lor the reception of the Elephant, Rliinoceros, Hippo- 

 potamus, kc. 



Pallial. Connected with the mantle or "pallium." 



Pallium (Lat. a cloak). The "mantle" of the Mollusca. 



Palpi (Lat. palpo, I touch). Processes supposed to le organs of touch, 

 developed froTu certain of the organs of the mouth in various Articulate 

 animals, and from the sides of the mouth in the Bivalve Molluscs. 



Papilla (L it. for a nipple). A minute soft prominence. 



Parapodia (Gr. pura, beside ; ^orfc5, feet). The lateral locomotive processes 

 or " foot-tubercles " of many of the Annelida, 



