8 
PYRGOMA. 
GENERIC CHARACTER: Shell sessile, of one piece sub- 
globular, bulging, convex above, the top perforated with 
a small orifice, which inclines to oval. Cover with four 
valves, scarcely apparent. 
* P. ANGLICUM. Magazine of Natural History, O S., vol- 
1, p. 475. It is rare that a full grown and complete 
Caryopbyllia Smithii (a species of coral) is brought from 
moderately deep water, without having a few specimens 
seated on its diverging plates; and I have rarely seen d 
under other circumstances. 
PEDUNCULATED CIRRHIPEDA. 
The shell supported by a tubular stalk, the base attached 
to some foreign body. 
ANATIFERA. 
GENERIC CHARACTER : The shell compressed at the 
sides, with 5 plates, which are contiguous and unequal ; 
the lower side plates largest. This genus is also termed 
Anatifa, and Anatifer. 
* A. LEVIS. Lepas Anatifera. Turt. Lin. Pen. Brit. Zo., 
vol. 4, pi. 38. fig. 9. Stew. Elem., vol. 2, p. 364. Mont. 
Test. Brit., vol. 1, p. 15. A. L. Crouch’s In., pi. 1> 
fig. 18. Barnacle. 
This which is termed the Dnck or clustering Barnacle, 
is the largest of the British species, sometimes measuring 
from the base of the shell to the point 2£ inches; and to 
distinguish it from the next, with which it is commonly 
confounded, it should be remarked as being more robust, 
and larger, while the stalk is comparatively shorter. The 
union of the larger plates is equal, and their margin rises 
forward in a rounded shape, again descending with a sweep; 
while in the next species the hinge is formed by the over- 
lapping of one of the plates; and their margin without rising 
passes forward, obliquely descending to the opening. In 
the latter also, the anterior plate leaves a larger membranous 
space at its produced portion, where it passes between the 
dorsal plate and the larger lateral. The dorsal plate of A- 
Levis is more ridged and elevated: the edge amounting 1° 
a keel at its bend. The graining on the surface of the 
plates, the absence of which in the present species has been 
deemed of sufficient importance to afford a trivial name, 
cannot be depended on for distinction. This species is found, 
sometimes in immense numbers, attached to wood that has 
been floating on the ocean; but instances of their occurrence 
are not nearly so frequent, as of the next species. Each 
kind is found occupying its own separate wreck, and may 
readily be distinguished, the present species by the clustering 
of its young on the stalk or shell of the parent, while o n 
