80 BALEA. 



at the apex by a conical operculum, consisting of four valves in 

 anterior and posterior pairs. Each valve of the shell is divided 

 into a rough triangular portion pointed towards the apex, and a 

 flat area on each side. — Obs. This description includes the Acasta 

 of Leach, which growing in sponges, has the base cup-shaped ; 

 Conopla-a of Say, which being attached to the stems of Gorgonia 

 and sea-weeds has the base elongated and lanceolate, and Chirona, 

 Gray. Balanus is the only genus of Sessile Cirripedes the shells 

 of which consist of six parietal valves, except coronula, which has 

 no shelly base, is flatter, and has the valves of the operculum 

 placed horizontally. The Balani are common in all seas, ad- 

 hering to rocks, corals, floating timber, and to each other. The 

 fossil species are found in the newest strata, at Bordeaux, Paris, 

 &c. Fig. 25. B. Tintinnabulum; 26.JcastaMontagui; 27. Balanus 

 galeatus, Conoplcea, Say. 



BALANIDEA. Bl. The second family of the class Nematopoda, 

 Bl. corresponding with Sessile Cirripedes, Lam., and consisting of 

 Coronular Multivalves, which are fixed, and in a manner soldered 

 to submarine substances, by the base of the shell ; as distinguished 

 from the Lepadicea, Bl., Pedunculated Cirripedes, Lam., which are 

 attached by a fleshy stalk. The Balanidea are composed of two 

 sets of valves, besides the shelly plate or base on which they rest. 

 The first, called the Parietal valves, are arranged so as to surround 

 the body of the animal ; the second, called the Opercular valves, 

 are placed horizontally, so as to cover the aperture. 



BALEA. Gray. Fam. Colimacea, Lam. — Descr. Spiral, turrited, 

 concentrically striated, sinistral, and covered with a thin brown 

 epidermis ; spire composed of numerous whorls, gradually in- 

 creasing in size ; aperture small, sub -quadrate ; peritreme entire, 

 slightly thickened, with a very slight fold on the columella ; axis 

 perforated. — Obs. A genus of small land shells, found in moss at 

 the roots of trees in Britain, not very nearly resembling any other 

 land shells, except Clausilia, from which they differ in not having 

 the clausium. They have been placed in Helix by De Ferrusac, 

 and in Pupa by Draparnaud. B. fragilis, fig. 296. Helix perversa, 

 Fer. Pupa perversa, Drap. 



