Shells found in Essex County. 49 



with prominent longitudinal ribs, and two angular elevations on 

 each. 



Journal of the Academy of Natural Sciences of Philadelphia, 

 Vol. VI., p. 265, pi. xi., fig. 16. 



Cabinet of the Society. 



ORDER II. PEDUNCULATA, i. e. having foot stalks to the 

 shells. Lam. 



ANATIFA. Latin, anas, a goose, and fero, to bear, (from an 

 old notion that the barnacle goose was produced from this shell. 

 Vide. Drummond's Letters to a Young Naturalist, p. 148, fig. 12.) 

 LAEVIS, Latin, smooth. Smooth anatifa. 

 SYN. LEPAS ANATIFERA. L. 

 PENTALEPAS LAEVIS. Blainville. 



Multivalve, furnished with a cartilaginous stalk or stem, by 

 which it is affixed to the bottoms of vessels and to floating tim- 

 ber. Edges of the valves covered with an orange membrane. 

 Number of the valves five. 



Griffith's^Cuv. Mollus. pi. 2, fig. 1. Bosc. coquilles, pi. 46, 

 fig. 1. Blainville's Manuel, pi. 84, fig. 3. Brown's Zool. Text 

 Book, p. 92, fig. 5. 



Cabinet of the Society. 



TEREDO. Greek, a ivoodboring worm. 

 NAVALIS. Latin, belonging to a ship. Ship worm. 



Found in the sheathing of vessels from foreign seas. Some- 

 times of extraordinary size : the tube attached to the shell, and 

 which is formed of calcareous deposit to line the drilled hole, 

 being two feet long. 



Griffith's Cuv. Mollusca, p. 122, pi. 8, fig. 2. Brown's Con- 

 chol. Text Book. pi. 18, figs. 18 to 22. 



Very fine specimens in the collection of the East India 

 Marine Society. 



