(sect, f), balanus cepa. 283 



35. Balanus cepa. PI. 7, %. 8 a — 8 c. 



&• 



Shell dirty reddish-purple, steeply conical : radii narrow : 

 basis obscurely porose. Scutum with the lines of growth 

 crenated : tergum with the spur truncated, broad as half the 

 valve, and dependi?tg beneath the basi-scutal angle as much 

 as half its own breadth. 



Hab. — Japan, attached to an Isis, Mus. Cuming. Attached to an oyster, 

 Mus. Stutckbury. 



As already stated, this species comes in all essential 

 respects very near to the last, though differing much in 

 appearance ; I have seen two sets of specimens, and two 

 sets of B. allium, and there was no variability or passage 

 in the points in which they differed ; hence I must consider 

 them as specifically distinct. 



Shell, steeply conical, strongly but bluntly ribbed longitudinally ; 

 coloured either all over dull reddish purple, or with the upper part only 

 pinkish purple : in one set of specimens, the yellow epidermis was 

 partially persistent. Radii narrow. Orifice small, ovate. The wall 

 of the carino-lateral compartment is very narrow. The internal surface 

 of the parietes is ribbed, but finely, and only in the lower part. The 

 septa, on the sutural edges of the radii, are finer than in B. allium. 

 Basis flat, obscurely permeated by pores. The largest specimen is 

 •25 of an inch in basal diameter. 



Scuta : these are longitudinally and finely striated ; the basi-tergal 

 corner is more rounded otf than in B. allium, and the articular ridge is 

 not nearly so prominent: internally, the adductor ridge is rather more 

 prominent. The Tergum is rather broader : its apex is produced into 

 a minute sharp point: the scutal margin is straight; the spur is 

 broader, and measured from the basi-scutal angle of the valve, con- 

 siderably longer; namely, as long as half the width of the basal margin 

 of the spur, whereas in B. allium it Js only about a quarter as long as 

 the basal margin of the spur : the lower edge of the spur is not here 

 so directly transverse to the longitudinal axis of the valve as in B. 

 allium : the external surface is not so flat as in that species, and a 

 depression runs down to the basi-scutal angle of the spur. 



Considering the difference in the shape and appearance of 

 the shell, with its narrow radii and small orifice; considering 

 the less strongly ribbed internal lamina of the parietes, the 

 finer septa on the sutural edges of the radii, the slight 



