214 BALANID.E. 



by five or six rows of very minute pores. I have not seen any other 

 instance of this structure. The internal lamina is ribbed, as usual, on 

 its inner surface, by the projection of the longitudinal septa. The ordi- 

 nary parietal tubes are open, to nearly the summit of the shell. The 

 radii arc rather thin, and unusually fragile; their summits are parallel 

 to the basis : their septa, as seen on the sutural edges, are extremely 

 thin and denticulated on both their upper and lower surfaces, on the 

 side towards the internal lamina : towards the external lamina, the 

 septa are simple, and the small square pores thus formed, are open or 

 not filled up. The alee have their summits extremely oblique, being 

 added to very little during the diametric growth of the shell ; the nar- 

 row margin, however, which is thus added, is coloured red, the rest of 

 the sheath being nearly colourless : the sutural edges of the alae arc 

 smooth. The basis has a thick, underlying, finely cancellated layer of 

 shell. 



Animal's body unknown. 



A young specimen, "2 of an inch in basal diameter, differed from the 

 above in being of a much paler purplish-brown. This species is distinct 

 from all its congeners, in its peculiar colour, and likewise in the struc- 

 ture of the inner lamina of the parietes. As already stated, it comes 

 nearer to B. decorus than to any other species. 



8. B alan us Ajax. PI. 3, fig. 1 a — 1 d. 



Balanus tintinnabulum {car.) Chenu. lllust. Conch., Tab. rJ, 

 fig. 8. 



Shell globulo-conical, often elongated in the rostro-carinal 



aa is, pale pink, smooth, extremely massive: parietal pores, 

 close to the basal margin, circular and very small. Scutum 

 with the articular ridge broad and reflexed. 



llab. — Philippine Archipelago, attached to Millepora eomplanata, Mus 

 Cuming. Mus. Brit, and Stutchbury. 



General Appearance. — Shell globulo-convex, sometimes much elon- 

 gated in its rostro-carinal axis ; smooth ; walls excessively strong, 

 massive, and heavy. Orifice oval, rather small in proportion to the size 

 of shell, this being chiefly due to the infolding of the upper part of the 

 rostral compartment. Parietes pale pink, feebly tinted with purple : radii 

 either paler, or tinted of a bright chesnut-brown : sheath rich purplish 

 chesnut-brown. Basal diameter of the largest specimen nearly 3£ of an 

 inch ; height 2| : another specimen had a basal longitudinal diameter of 

 2*9 of an inch, and a transverse diameter of only L'6; this great dif- 

 ference in the two diameters being caused by the prolongation of the 

 basal portion of the rostrum in the line of the branch of the Miliepora, 

 to which the ^hell had adhered ; the height of this same specimen was 



