BALANUS. 17 
4. Batanus concavts, Tab. I, fig. 4a—4p. 
BaLaNus concavus. Bronn. Italiens Tertiar-Gebilde (1831) et Lethzea Geognostica, 
b. ii, s.1155 (1838), Tab. 36, fig. 12.1 
—_— CYLINDRACEUS, var. Cc. Lamarck. Animaux sans Vertébres (1818). 
LEPAS TINTINNABULUM. Brocchi. Conchologia Sub-Appen., t. ti, p. 597, (1814). 
B. parietibus et bast, sed non radiis poris perforatis ; testé albo cum roseo aut obscure 
purpureo longitudinaliter picta, interdum puré albd. WScuto longitudinaliter tenuiter striato : 
interne, adductoris cristé admodum aut modicé prominente. 
Parietes and basis, but not the radii, permeated by pores; shell longitudinally striped 
with white and pink, or dull purple; sometimes wholly white; scutum finely striated lon- 
gitudinally ; internally, adductor ridge very or moderately prominent. 
Fossil in Coralline Crag, (Ramsholt and Sudbourne) rarely in the Red Crag (Sutton); Mus. 
S. Wood, Bowerbank, Lyell, J. de C. Sowerby, Tennant. Sub-Appenine formations, near Turin, Asti, and 
Colle in Tuscany, Mus. Greenough, &c. Tertiary bed, near Lisbon, Mus. D. Sharpe and Smith. Bordeaux (?) 
Mus. Lyell. Tertiary beds, Williamsburg ; and Evergreen, Virginia, Mus. Lyell. Maryland, Mus. Krantz. 
Pleiocene formations? near Callao, Peru, Mus. Darwin. 
Recent at Panama; Peru; S. Pedro, California; Philippine Arch.; Australia. 
This species has caused me much trouble. It will be convenient first to make a few 
remarks on the recent specimens; I examined several from Panama and California, which, 
though differing greatly in colour, resembled each other in their scuta having the adductor 
ridge extremely prominent, and in having (Tab. I, fig. 4”) an almost tubular cavity for 
the attachment of the lateral depressor muscle,—characters which at first appeared of high 
specific value; but I soon found other specimens from Panama in which these peculiarities 
were barely developed. I then examined a single specimen from the Philippine Archi- 
pelago, resembling in external appearance one of the Panama varieties, but differing in the 
scuta being externally strongly denticulated in lines instead of being merely striated,—in 
the adductor ridge being far less prominent,—and in the spur of the tergum being broader 
and more truncated ; I therefore considered this as a distinct species. I then examined a 
single white rugged specimen from the coast of Peru, which differed from the Philippe 
specimen in the shape of the well-defined denticulations on the scuta, and in some other 
trifling respects, and in the segments of the posterior cirri bearing a greater number of 
spines; with considerable doubt, I also named this as distinct. But when I came to 
1 I suspect that B. pustularis, miser, and zonarius, all figured by Miinster, in his ‘ Beitrage,’ b. iii, 
Tab. 6, may be this species. 
2 I procured this specimen from the Island of S. Lorenzo, off Callao; it was imbedded, together with 
seventeen species of recent shells and with human remains, at the height of eighty-five feet. 
3 
