(sect, c), bai.anus spongicola. 225 



15. Balanus spongicola. PI. 4, fig. 1 a — 1 d. 



Balakus spongicola. Brown's Illustrations of the Concbology of 

 Great Britain (1827), pi. 7, fig. 6: 2d edit. (1844), pi. 53, 

 figs. 14—16. 



Parietes generally smooth, sometimes longitudinally folded ; 

 coloured pink : orifice toothed. Scutum longitudinally striated. 

 Tergum, with the apex produced, without a longitudinal 

 furrow ; spur truncated, about one third of ividth of valve. 



Far. with the walls slightly folded longitudinally . 



Hab. — South coast of England, and Tenby in South Wales, often imbedded 

 in sponges; attached also to shells and rocks in deep water; Mus. Brit., 

 Jeffreys. Algiers, on Mytili and Serpulse, with B. perforates, Mus. Mac Andrew. 

 Madeira, with B. tidipifonnis, Mus. Lowe. Lagulhas Bank, Cape of Good 

 Hope, on detached kelp, with B. Capensis, Mus. Sir J. Boss. Imbedded in sponge 

 with Acasta spongites, Mus. Bowerbank. Var. West Indies. 



Fossil in Coralline Crag, Mus. S. Wood. 



General Description. — Shell tubuio-conical ; orifice of moderate size, 

 rather deeply toothed ; colour dull pink, or purplish, or dark flesh- 

 colour ; sometimes the radii are paler, sometimes of the same colour 

 with the parietes. Surface smooth when well preserved, having trans- 

 verse rows of minute spines. In the West Indian variety the walls are 

 slightly or much folded, but I will describe this form separately. Size 

 of largest specimen (Mus. Jeffreys), *6 of an inch in basal diameter. 



Senium, with fine ridges radiating from the apex, and with the lines 

 of growth, crenated : internally, the articular ridge is small, adductor 

 ridge short and barely distinct: there is a rather deep and narrow pit 

 for the lateral depressor muscle. The whole valve is much thinner than 

 in B. irigonvs, which in most respects it closely resembles. Tergum, 

 with the apex pinkish purple, produced or beaked, but the beak is not 

 needle-like, as in B. psittacus and its" allies, for the carina] margin is 

 perfectly preserved up to the tip. Externally the valve is nearly, flat, 

 for the longitudinal furrow is very shallow. The spur is about one 

 third of the width of the valve ; its lower end is abruptly truncated : in 

 European specimens (1 b) the whole basal margin, on the carinal side, 

 slopes down to the spur in a straight line, which, together with the 

 sharpness and production of the basi-scutal angle of the spur itself, 

 gives to the whole valve a peculiar appearance : in the specimen ( ! c) 

 from the Lagulhas Bank, the basal margin on the carinal side is a little 

 more hollowed out, but it is quite impossible to doubt about the specific 

 identity of these specimens : in the West Indian variety (1 d) the basal 



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