212 OVULUM. 



characterized by strongly angulated folds, throws out arms from 

 the lower valve, by which they are attached to stems of sea-weed, 

 &c. Fig. 180, 0. edulis. Fig. 181, 0. folium. (Dendostrea, 

 Sw.) Fig. 182, Gryphsea incurva. Fig. 183, Exogyra conica. 



OTIDES. Bl. The first order of Scutibranchiata, Bl. containing 

 the genera Haliotis and Ancylus. 



OTION. Leach, (omov, a little ear.) Order. Pedunculated Cir- 

 ripedes, Lam. — Descr. Body sub-quadrate, supported on a fleshy 

 pedicle with a gaping aperture and two posterior auricular tubes; 

 valves five, separate, two semilunar, placed* at the sides of the 

 aperture, two terminal, very small, one dorsal, minute. — Obs. 

 Otion differs from Cineras in having two cylindrical posterior 

 tubes, and in the extreme minuteness of three out of five of the 

 valves. Found on spars floating in the sea, &c. 0. Cuvierii, 

 (Lepas aurita, Linn.) Fig. 43, 0. Cuvieri. 



OTIS. Humph. Auricula, Lam. 



OVATE. (Ovatus.) Egg-shaped or oval. 



OVEOLITHES. Montf. A microscopic shell resembling Bulla. 



OVIPAROUS MOLLUSCA. Those which produce their young in 

 eggs. Used in distinction from the Viviparous Mollusca, 

 whose young are perfectly formed before they leave the body of 

 the parent. 



OUTER LIP. See Labrum. 



OVULUM. Brug. (Ovum, an egg, dim.) Fam. Convoluta, Lam. 

 Angyostomata, Bl. — Descr. Ovate or fusiform, smooth, convolute, 

 spire covered ; aperture narrow, with a canal at each extremity ; 

 outer lip crenulated, inflected ; inner lip smooth, callous towards 

 the spiral extremity ; dorsal area wide, sometimes indistinctly 

 marked. — Obs. The Ovula were placed by Linnaeus in his genus 

 Bulla, from which they are very remote. They differ from Cyprsea 

 in having the inner lip smooth. We have given representations 

 of their different forms as follows: 0. Ovum, fig. 442. 0. ver- 

 rucosum, (Calpurnus Montf.) fig. 441. 0. Volva, the weaver's 

 shuttle (Radius, Montf.) fig. 442. 0. gibbosum, (Ultimus, 

 Montf.) fig. 443. 





