THE CRUSTACEA OF NEW JERSEY. 155 



Balanus Dumeril, Zool. Analyt., 1806, p. (170) 2^;^. Atypic. (Type Lepas 



balanus Linnaeus.) 

 Messula Leach, Zool. Journ., II (VI), 1825, p. 210. Atypic. 

 Chirona (Gray) Lyell, Philosoph. Trans. Roy. Soc. London, pt. I, 1835, 



P- 27- Type Lepas tulipa Miiller, monotypic. 



Compartments six. Basis calcareous or membranous. Oper- 

 cular valves sub-triangular. World-wide in warmer seas. 



Key to the species. 



a. Basis membranous. balanoides 



aa. Basis and radii not permeated by pores; parietes permeated by pores. 



crenatus 

 aaa. Radii not permeated by pores ; parietes and basis permeated by pores. 



eburneus 



Balanus balanoides (Linnaeus). 



Plates 45 and 150, Figure ii. 



Rock Barnacles. 



Lepas balanoides Linnaeus, Faun. Svecica, Ed. 2, 1761, p. 515. Atlantic seas. 

 Balanus balanoides Darwin, Monogr. Cirrip., 1854, p. 267, PI. 7, fig. 2a-2d. 

 Delaware. 



Leidy, Journ. Acad. Nat. Sci. Phila., (2) III, 1855, P- i5i- Atlantic 



City and Beesley's Point, New Jersey. 



S. I. Smith, Rep. U. S. F. Com., I, 1871-72 (1873), p. 579. Whole 



North Atlantic. 



R. Rathbun, Rep. Fisher. Ind. U. S., I, 1884, p. 828. Our coast (East- 



ern U. S.). 



Description. — Shell in medium and old examples almost in- 

 variably folded lengthwise and irregularly, dirty-white or pale- 

 brown, punctured from outer lamina being corroded. Young 

 Avith surface usually white and smooth. Shell sometimes much 

 depressed, generally conical, but when crowded together cylin- 

 drical or club-shaped. Isolated examples occasionally become 

 cylindrical. 



Orifice of shell in elongated examples usually deeply toothed. 

 Radii always narrow, sometimes extremely so, and summits 

 smooth and rounded. Opercular valves like those in next 

 species. Scuta thicker and tips less reflexed. articular ridge 



