393 
BALANUS. 
Gen. Char. Conical, composed of four or six valves 
laterally articulated and fixed by a base. Moutb 
at the top, having within two or four valves like 
an operculum. 
The operculum is seldom found in extraneous Fossils, 
because in the recent specimens it is united only by a mem* 
brane. Many of the species are gregarious, when the form 
becomes prismatic instead of conical : the lateral valves are 
generally composed of tubes. 
BALANUS tesselatus. 
TAB. LXXXIV. — Fig. 1. 
Spec. Char. Obliquely conical, thin; valves six, 
obscurely ribbed, smooth ; interstices finely tes- 
sellated; aperture oval. 
Height rather less than the diameter of the base, the longest 
diameter of the aperture about half as much. 
This species, from Bramerton in Norfolk, has some 
resemblance to recent species, yet I do not know that it can 
be referred to any known one. It is thinner for its size 
than most reliquia. 
