(sect, f), balanus B1SULCATUS. 293 



the scutum, in that species, a single little ridge, foreshadowing, as it 

 were, the crests for the lateral scutal depressores, so remarkable in our 

 present species. In the structure of the shell and of the basis, B.Jlos- 

 culus is much more closely related to the last species, or B. imperator. 

 If it had been possible to have arranged the species in a single line, 

 B.Jlosculus ought undoubtedly to have been placed between B. cariosus 

 and imperator. 



41. Balanus bislilcatus. PI. 8, fig. 6 a — 6 c. 



Balanus sulcatinus (?) Nyst, apud D'Omalius (sine descript. 



aut tabula), Geologie de Belgique, 

 1853.* 



Badii with their upper margins oblique and smooth; 

 sutwral edges smooth ; basis permeated by large pores. 

 Scutum narrow », with from hoo to four longitudinal furrows : 

 tergum with the spur very short, broad as half the valve. 



Var. plicatus, with the walls deeply folded ; radii narrow, with their 

 upper margins very oblique. 



Fossil in Coralline Crag, Hamsholt, Gedgrave, Sutton ; Mus. S. Wood, 

 Bowerbank, J. de C. Sowerby. Rauville, dans le Cotantin, Mus. G. B. Sowerby. 

 Var. plicatus, Coralline Crag, Sutton, Mus. S.Wood. Bolderberg, near Hasselt, 

 Belgium, Mus. Bosquet. 



General Appearance. — Shell conical or tubulo-conical, often rather 

 globose ; walls frequently thin, either very smooth, or deeply plicated 

 longitudinally : occasionally the same specimen is smooth in the upper 

 part, and strongly plicated in the lower. The Radii in tbe larger speci- 

 mens are wide, and with their upper margins only slightly oblique; in 

 the smaller, they are narrower and much more oblique, but in each case 

 their upper margins are smooth and slightly bowed. Colour apparently 

 originally nearly white, but with the alee generally, in the smaller 

 specimens, clouded with a dark tint: the radii are usually striped 

 feebly in longitudinal lines. Basal diameter of largest specimen '8 of 

 an inch ; but this seems to have been an unusual size. 



Scuta : narrow, with the basal margin forming an unusually small 

 angle with tbe occludent margin ; surface slightly convex, with lines 



* I am indebted to M. Bosquet for a specimen, bearing this name and refer- 

 ence, found in the ' Systeme Bolderien' of Dumont, (miocene according to Sir 

 C. Lyell) at Bolderberg. The specimen consists of a rostrum, with a portion 

 of the base attached ; and as these parts are in some degree characteristic, 1 

 fully believe this specimen to be the B. bisulcatus. I hope hereafter to give in 

 the Palseontographical Series fuller illustrations of this and the following fossil 

 species. 



