120 SESSILIA. BALANUS. 
ORDER II. — SESSILIA. 
Destitute of a peduncle; body enclosed in a multivalve 
shell, attached by its base to marine bodies ; mouth situated 
at the upper and interior portion of the body. 
Genus 1.— BALANUS., — Lamarck. 
Generic Character. — Shell sessile, conical, or subconic, 
closed at the base by a testaceous plate, which adheres to 
extraneous substances, consisting of four articulated valves ; 
aperture subtrigonal, or elliptical, and shut by an operculum 
composed of four valves. 
Balanus tessilatus. Plate X. fig. 4. 
The Balani are exceedingly variable in form, depending upon the shape of the 
substance to which they are affixed. Fossil species occur in the newer forma- 
tions, the one we have figured was found at Bramerton, Norfolk. They also 
occur in the marine sands of the Blue marls of France and Italy. 
