TETRACLITA POROSA. 329 



1. Tetraclita porosa. PI. 10, fig. 1 a — -1 m. 



Lepas porosa. Gmelin. Syst. Naturae, 1789.* 



Balanus squamosus. Bruguiere. Encyclop. Method., 1789, PL 165, 



fig. 9, 10. 

 Lepas fungltes. Spengler. Skrivter af Naturliist. Selskabet, 1 B., 



1790. 

 — porosa. Wood's General Conchology, PI. 9, fig. 4, 1815. 

 Tetraclita squamulosa. Schumacher. Essai d'un Nouveau Syst., 



&c., 1817. 

 Balanus stalactieerus. Lamarck. Animaux sans Vertebres, 1818. 



— — Clienu. Illust. Conch., PI. 4, fig. 6, 7. 



Asemus porosus. Ranzani. Memoire di Storia Naturale, Tab. 3, 



fig. 32—35. 

 Conia porosa. Soicerby. Genera of Recent and Fossil Shells, 



Plate, 1823. 

 — — Leach, (sine descript.) Encyclop. Brit. Supple- 



ment, vol. 3, 1824, Tab. 57. 



Radii rarely present, when present narrow ; even the 

 sutures often absent: shell steeply conical, with the surface 

 generally corroded, and haviny a stalactiferous appearance. 



Var. (1) communis (PL 10, fig. la): outer lamina of shell almost 

 wholly removed ; the -portion preserved, as well as the exposed parietal 

 tubes, gray, or pale dirty brown, or dull purple. 



Var. (2) nigrescens (PL 10, fig. 1 c) : outer lamina of shell almost 

 wholly removed; the portion preserved, and the exposed parietal tubes, 

 very dark purple or inky black. 



Var. (3) viridis ; outer lamina of shell almost wholly removed ,• the 

 portion preserved, and the exposed parietal tubes, green ; under surface 

 of opercidar valves clouded green. 



Var. (4) rubescens (PI. 10, fig. 1 b) : outer lamina of shell almost 

 wholly removed ; the portion preserved, and the exposed parietal tubes, 

 pale reddish-purple, or peach-blossom purple ; under surfaces of oper- 

 cidar valves often reddish purple ; terga often rather narrow, with the 

 spur somewhat pointed, and with the basal margin on the carinal side 

 sloping, or not making an angle with the spur. 



* As Gmelin and Bruguiere published the same year, I do not know which 

 comes first, but I have adopted the best known name. Most authors give, 

 amongst their references, Chemnitz, vol. 8, Tab. 98, fig. 836, 837, but the 

 accompanying description is more applicable to T. serrata of this work than to 

 T. porosa ; without a figure or description, however, of the under side of the 

 scutum it is impossible to decide. Several authors, also, give Lepas cariosa of 

 Pallas, as a synonym ; this, however, is the Balanus cariosus of this work. 



