CIRRIPEDES. MOLLUSCA. BALANUS. 17 



This, like the following species, may be only one of the Protean 

 forms of Lepas balanoides of Linnaeus. In a shell of so anomalous 

 a character, I have chosen to abide by what is certain ; and I think it 

 is certain, that the shell before me is the same as the shells of 

 Montagu and Donovan. It accords exactly with the description by the 

 former, and the figures by the latter. It attains a much larger size 

 than the next species, and may be easily distinguished from it, under 

 any disguise, by its simple opercular valves, and their acute, diverging 

 points. The exterior is more rugged than that of any other species I 

 have seen. 



BALANUS OVULA'RIS. 



Shell small, white, variable in shape, more or less furrowed ex- 

 ternally ; aperture rhomboidal ; opercular valves obsoletely striated, 

 the anterior ones shortest and acute, the posterior ones deeply notched 

 near the obtuse summit. 



FIGURE 7. 

 State Coll., No. 252. Soc. Cab., No. 2080. 



Balanus ovularis, LAM. ; An, sans Vert., v. 660. 



Lepas balanoides, LIN. ; Syst. Nat., 1108. 



Lepas balanus, WOOD ; Gen. Conch., pi. 7, f. 3. Index, pi. 1, f. 11. 



Under this name I would notice our most common barnacle. 

 The few characters given to the species by Lamarck would apply 

 to this shell with less reservation than any other description I 

 have seen. It is found, of all shapes and ages, crowded together 

 upon every rock or wooden fixture between high and low water 

 mark ; and it is for the most part confined to stations where it is 

 half the time left by the tide, while the preceding species seems 

 to frequent the deep water. 



In shape it is very various. Sometimes it has a low, conical 

 form, its height being less than half of its base ; again, its height 

 is three or four times as great as the diameter of its base, and its 

 summit broader than its base. In its early stages it is smooth, SQ 

 that the valves are always plain at their summits ; but soon the 

 base becomes scolloped by four or five grooves on each valve, and 

 these grooves then continue on all the subsequent growth of the 

 shell. The summit is usually even, as if all the points of the 

 valves had been clipped off ; but in an exuberant growth they are 

 elevated irl the form of thin, blunt plates. The aperture is dia- 

 3 



