THE CRUSTACEA OF NEW JERSEY. 159 



Remarks. — A species of very wide distribution. Very com- 

 mon, and usually attached to shells and Crustacea in deep water, 

 sometimes on ships' bottoms. It does not, apparently, attach to 

 rocks uncovered by the tide, though is found on floating timber, 

 sticks, fuci and occasionally on pebbles at the bottom of the sea. 



Specimens were obtained at Cape May by Mr. C. LeR. 

 Wheeler. 



It is also known in a fossil state from Canada and Europe. 



Balanus eburneus Gould. 



Plates 47 and 150, Figure 12. 



Ivory Barnacle. 



Balanus eburneus Gould, Nat. Hist. Mass., VII, 1841, p. 15 (floating wood, 



Crustacea, shells, etc.). Massachusetts. 

 • Darwin, Monogr. Cirrip., 1854, p. 248, PI. 5, figs. 4a-4d. United 



States, from about lat. 42° to Charlestown. 



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

 setts Bay to West Indies. 



R. Rathbun, Rep. Fisher. Ind. U. S., I, 1884, p. 828. Massachusetts 



Bay to West Indies. 



M. J. Rathbun, Occas. Papers Boston Soc. N. Hist., VII, No. 5, 1905, 



p. 81. Long Island Sound. From Salem, Massachusetts, southward. 



Description. — Shell conical or almost tubular, white, surface 

 very smooth, covered by thin yellowish epidermis but radii 

 naked. 



Orifice large, rhomboidal to pentagonal, moderately toothed. 

 Scutum plainly striated longitudinally, teeth on occludent edge 

 small, internally upper surface roughened. Articular ridge promi- 

 nent and slightly or not at all reflexed, pit for adductor muscle 

 distinct, and adductor ridge variably prominent, almost con- 

 fluent with articular ridge. Tergum with basal margin on 

 carina! side of spur sometimes deeply' or slightly hollowed 

 out, though rarely at all. When much hollowed valve almost 

 two-pronged and carinal prong narrower than spur. No dis- 

 tinct longitudinal furrow on tergum, but whole scutal edge 

 projects above general surface of valve. In carinal edge, in 

 upper part, a remarkable convexity or protuberance in same 



