(sect, c); balanus concavus. 235 



Southern America, and on the whole west coast of that continent. It 

 is allied to that species, and differs from most other species, in the 

 general form of the shell, its small orifice, narrow radii, and often 

 deeply cup-formed basis. It agrees to a certain extent in the colouring, 

 though the purple here is much more prevalent, and is not confined to the 

 shelly matter filling up the parietal tubes. It agrees with that species in 

 the general structure of the scutum; but the two or three deep, longi- 

 tudinal furrows are here absent ; and the minute ridge, parallel to and 

 almost under the adductor ridge, is a peculiarity confined to this and 

 very few species in the genus. The terga differ from those of B. Icevis, 

 chiefly in the spur being narrower, and in the apex being beaked. 

 Lastly, the highly protuberant segments of the one ramus in the first 

 cirrus, and of both rami in the second pair, are here remarkable. With 

 regard to the varieties, I have nothing to add to their short diagnostic 

 characters above given. 



18. Balanus concavus. PL 4, fig. 4 # — 4 e. 



Balanus concavus. Broun. Italiens Tertiar-Gebilde (1831) et 



Lethsea Geognostica, b. ii, s. 1155 (1838), 

 Tab. 36, fig. 12.* 

 — cylindbaceus, var. c. Lamar ck. Animaux sans Vertebres 



(1818). 

 Lepas tintinnabulum. Brocchi. Conchologia Sub-Appen., t. ii, 



p. 597 (1814). 



Shell longitudinally striped with white a?idpinfc; or dull 

 purple ; sometimes wholly white. Scutum finely striated 

 longitudinally ; internally, adductor ridge very or moderately 

 prominent. 



Hah. — Panama ; Peru ; S. Pedro in California ; Philippine Archipelago ; 

 Australia. Mus. Brit., Cuming, Stutchbury, Aug. Gould. 



Fossil in Coralline Crag, England ; Mus. Brit., S. Wood, Bowerbank, Lyell, 

 J. de C. Sowerby, Tennant. Sub-Appennine formations, near Turin, Asti, Colle 

 in Tuscany, Mus. Greenough, &c. Tertiary beds, near Lisbon, Mus. 1). Sharpe 

 and Smith. Bordeaux (?) Mus. Lyell. Tertiary beds, Williamsburg; and 

 Evergreen, Virginia, Mus. Lyell. Maryland, Mus. Krantz. Recent formations-}" 

 near Callao, Peru, Mus. Darwin. 



This species has caused me much trouble. Looking first 

 to the recent specimens, I examined several from Panama 



* I suspect that B. ptcslularis, miser, and zonarius, all figured by Minister, in 

 his ' Beitrage, 5 b. hi, Tab. 6, may be this species. 



f 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. 



