170 SESSILIA. 



contiguous and unequal; the lower lateral ones the largest; 



the whole of them united and kept together by means of | 



thin membranes. I 



Anatifa Icevis The Smooth Anatifa. Plate XIX. ! 



fig. 5. With five smooth valves ; the dorsal valve rounded I 

 at the sides, and slightly carinated ; peduncle very long, of 

 a scarlet colour. Inhabits the British seas. 



This and other species, popularly called Barnacles, were formerly j 



supposed to give origin to ducks and geese, the filaments having been i 



taken for feathers. | 



i 



OEDER n.-SESSttIA. 



Body without a peduncle, and enclosed in a multivalve 

 shell, seated immediately on marine bodies, or rocks ; mouth 

 and tentacula placed in the apex, or upper part of the body. 



* With a bivalve operculum. 

 Genus \.— VYRGOM A.— Savigny. 



Generic Character. — Sessile, univalve, subglobular, ven- 

 tricose, convex above, and open at the apex ; opening small, 

 elliptical, provided with a bivalve operculum. 



Pyrgoma crenata The Crenated Ptrgoma. Plate 



XIX. fig. 6. With radiated ribs, and crenated round the 

 margins ; of a pale violet colour. 



Genus 2.— CREUSIA Leach. 



Generic Character Body sessile, subglobular, enclosed 



in an operculated shell ; having three or four pairs of ten- 

 tacular arms. Shell sessile, fixed, orbicular, convexo-coni- 

 cal, consisting of four united unequal valves; operculum 

 internal and bivalve. 



Creusia verruca The Warted Creusia. Plate XIX. 



fig. 7. White, slightly depressed, with interlocked obliquely 



