BULLA. DIPPER. 
from B. aperta, in its elongated and ear-shaped form : 
length three quarters of an inch ; breadth half an inch. 
When alive, the animal completely envelops the shell, 
from which circumstance it naturally falls into this family. 
Western coasts, Dublin bay, Scotland, v. v. 
14. Bulla tentaculata. Armed Dipper. 
Linn. Trans, xi. pi. 12. f. 5, 6*. 
Shell so extremely similar to the B. haliotoidea, that 
Montagu observes no distinction can be conveyed by de¬ 
scription or figure, except that it is rather more depressed 
and opake. To the animal alone, therefore, must we refer 
for the actual identity of each, which in their structure is 
materially and essentially different. The animal of B. ha¬ 
liotoidea is represented at fig. 0, in the Vignette to the se¬ 
cond part of Montagu’s Testacea Britannica; and that of 
B. tentaculata as above quoted. 
At the salt-rock, in the estuary of Ivingsbridge, Devon : 
rare. 
15. Bulla flexilis. Flexible Dipper . 
Laskey, Wern. See. i. pi. 8. fig. 6. 
Shell oval, transparent, horn-color, flexible when wet, 
very brittle when dry, white and opake at the crown, 
where there is a single oblique volution. In shape and the 
form of the involution it exactly resembles B. haliotoidea, 
bat is much more distinctly wrinkled : length half an inch. 
Found by Captain Laskey, at Dunbar: very rare. 
16. Bulla Plumula. Feather Dipper. 
Montagu, pi. 15. f. 9, and Vignette 2. f. 5. 
Shell oblong-oval, flat, thin, transparent, concentrically 
wrinkled, with two or three ray-like impressions from the 
base to the crown: color yellowish-white, tinged with 
brown at the base, the other end folded into a single very 
minute volution : aperture extending over the whole shell, 
slightly turned in at the crown to form the very minute vo¬ 
lution: length half an inch; breadth nearly a quarter. 
On Milton sands, Devon: very rare. v. fti. 
17. Bulla membranacea. Membranous Dipper. 
Linn. Trans, xi. pi. 12. f. 4. 
Shell oval, flat, extremely thin and delicate and some- 
d what 
