300 BALANID^E. 



My materials consist of a beautiful series of specimens in 

 Messrs. Wood and Bowerbank's collections ; but unfor- 

 tunately only a single young specimen had its opercular 

 valves preserved. Not one specimen of the very curious 

 variety (a) had opercular valves, yet I cannot feel any doubt 

 about its being only a variety, caused by its attachment 

 to a thin cylindrical branch of a coral, instead of to a 

 foliaceous Bryozoon ; it will, however, be convenient to give 

 a separate description of this very remarkable form. With 

 respect to var. (b), both sets of specimens came to me 

 with the name B. stellaris, of Bronn ; but as Bronn dis- 

 tinctly states, that in his species the parietes are porose, and 

 as such is not here the case, this cannot possibly be that 

 species : these specimens did not possess their opercular 

 valves, and therefore cannot be identified with certainty. 



General Appearance. — Shell conical, with the orifice rather large, 

 and rhoraboidal. The surface is very smooth, except in var. (b.) from 

 the Continent, in which it is rugged and longitudinally folded. The 

 colour is ochreous-brown (chiefly no doubt derived from the imbedding 

 substance) tinged with red. The radii often have a much darker and 

 more distinct red tint; they are sometimes longitudinally striped with 

 dirty white. The radii are broad, with their summits straight, and very 

 slightly oblique ; in var. b, however, they slope at an angle of about 

 45°. Basal diameter of largest specimens *6 of an inch; but this is 

 an unusual size. 



Scuta (from a young individual), with the growth ridges little 

 prominent. Internally the articular ridge is moderately prominent, 

 with its lower end very obliquely rounded off; there is no adductor 

 ridge ; there is a minute pit for the lateral depressor muscle. Terga, 

 with a slight longitudinal depression extending down to the spur : spur 

 short, with its lower end almost square or truncated, about one fourth of 

 width of valve, and placed at about half its own width from the basi- 

 scutal angle. Internally, the articular ridge is prominent ; the crests 

 for the tergal depressores are feebly developed. 



Parietes, moderately thick and generally strongly ribbed inter- 

 nally, without parieted pores. Radii, wide, with their upper margins 

 straight, not smooth or rounded, and very slightly (or, in var. b, 

 moderately) oblique ; their sutural edges have well-developed septa, 

 which are denticulated: the interspaces between the septa are filled 

 up solidly. The alee have their upper margins oblique : they are only 

 slightly, and sometimes not at all, added to above the level of the oper- 

 cular membrane : their sutural edges are smooth. The basis is thin, 

 but plainly porose. 



Var. (a). — With respect to this remarkable variety, any one would at 

 first think it specifically distinct. The shell is much compressed, or clou- 



