THE CRUSTACEA OF NEW JERSEY. 157 



within tidal limits. Darwin says it occurs attached, often con- 

 tinuously coating many square feet of the surface, to rocks, 

 pebbles, wooden piers, littoral shells and ulna2. The most 

 northern point from which he received material was N. Lat. 

 66° 34^ in North America, and the most southern point was 

 Delaware Bay in Lat. 39°. Leidy records it from Atlantic 

 City and Beesley's Point. Mr. Witmer Stone found it at Point 

 Pleasant. Aly specimens from Ocean City. 



Balanus crenatus Bruguiere. 



Plate 46. 



Balanus crenatus Bruguiere, Encyclop. Method, (des Vers), I, 1789 (1792), p. 



168. English Coasts and North Sea. 

 Darwin, Monogr. Cirrip., 1854, P- -61, PI- 6, iig. 6a-6g. United 



States. 

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



Sound to the West Indies. 



Description. — White, usually of dirty tint, from yellowish or 

 brownish persistent epidermis. Shell conical, generally with 

 parietes rugged and irregularly folded longitudinally, sometimes 

 much depressed and extremely smooth, often cylindrical and 

 very rugged, occasionally club-shaped with upper part much 

 wider than lower, and latter sometimes with extremely narrow 

 parietes like mere ribs, also with wide radii. 



Orifice in cylindrical varieties often most deeply toothed. Radii 

 generally narrow, with jagged oblicjue summits, sometimes so nar- 

 row as to form mere linear borders to compartments. Orifice 

 rhomboidal, passing into oval, very deeply or but slightly toothed. 

 Scuta with lines of growth but little prominent, surface generally 

 covered by disintegrating membrane. Upper ends usually little 

 reflexed, so that tips project freely as small flattened points. 

 Articular ridge internally highly prominent and somewhat re- 

 flexed, no adductor ridge, very distinct impression for adductor 

 muscle and depression for lateral depressor muscle small but 

 variable. Terga rather small, short spur placed at rather less its 

 own width from basi-scutal angle, and basal edge slopes little 

 to\Vards spur, of wdiich lower end rounded or variably bluntly 



