INDEX-GLOSSARY. 389 



Osphradium (6<r<pd<koi;, anything sharp-smelling ; vfr^paivo^ai, I smell) 



The olfactory organ of Molluscs, probably serving to test the respira- 



tory quality of water, 121. 



Ossicle Auditory o. = malleus, incus, stapes, and os orbiculare, 273. 

 Ossification, 188. 

 Osteoblast (oo-Teoi/, a bone ; /3\ao-Tya>, I grow ; /3\a<rr6s, something that 



grows) A bone-forming cell, which becomes modified into a bone- 



corpuscle, 188. 

 Ostium (ostium, a door, an entrance), in the Crayfish One of six valvular 



slits in the wall of the heart, 97. 

 Otocyst (ous, WTOS, the ear; KU<TTIS, a bag, a bladder) The auditory sac, 



121, 134. 

 Otoliths (ous, tores, the ear ; Xi0oe, a stone) Concretions (or foreign particles) 



found within an auditory sac or membranous labyrinth, 121, 134, 219. 

 Ovary (ovum, an egg) The organ producing ova; Hydra, 23; Distoma, 33; 



Taenia, 42; Ascaris, 52; Lumbricus, 64; Hirudo, 80; Astacus, 100; 



Anodonta, Unio, 118; Amphioxus, 144; Scyllium, 167; Rana, 207; 



Columba, 251 ; Lepus, 298. 

 Oviduct The duct conducting the ova to the exterior or into the urino- 



genital canal, 33, 64, 80, 100, 119, 131, 167, 207, 251, 299, 333. 

 Oviparous (ovum, an egg; pario, I produce) Laying eggs, 168, 308. 

 Ovogenetic, 74. 

 Ovum The female sexual cell, 23, 34, 72, 73, 80, 100, 131, 144, 167, 207, 



251, 299. 



Oxidation, 10. See Respiration. 

 Oxygen, 10. 

 Oxyuris, 53. 



P 



Pacific islands, 349. 



Palsearctic, 350, 351. 



Palate, 275, 284, 325 ; cleft p., 325. 



Pallial Belonging to the mantle, 110. 



Palp, labial, 112, 113, 120. 



Pancreas (Tray /ejects, the sweet bread) A digestive gland opening into the 



intestine, and secreting a fluid which converts starch into sugar, 



proteid into peptone, &c., 160, 191, 244, 287, 288. 

 Pancreatic juice, 161, 194, 245, 289. 

 Panniculus carnosus, 270. 

 Papilla A small projection ; Head p. , 28, 36 ; Circumvallate p. , 284, 329 ; 



Filiform p., 189; p. Foliata, 284, 329; Fungiform p., 189; Genital p., 



41, 207, 251; Tactile p., 53; Urinary p., 167. 



