Sessilia.] 



MOLLUSCA. 



121 



Shell subconic, depressed ; with from seventeen to nineteen 

 nearly equidistant, divergent, smooth ribs, extending consider- 

 ably beyond the base, which is nearly circular ; in some in- 

 stances two or three are situate closer to each other than the 

 rest ; aperture small, subovate, with its edge very regular and 

 even ; operculum pale pink, four-valved, and very obtuse at the 

 apex ; anterior valves striated obliquely. 



Not uncommon on many of the British and Irish coasts. 



The very distinct and charcteristic specimen from which we 

 made our drawing of fig. 3, pi. LIV, was found at Seaton, 

 Northumberland, by W. C. Trevelyan, Esq., and is in the 

 cabinet of Sir John Trevelyan, Bart., at Wallington. 



5. Balanus candidus, pi. LIV, f. 8, 9, 10, 11, 12. 

 Balanus Scoticus, First Ed., pi. 6, f. 8, 9, 10, 11, 12; Bala- 

 nus candidus, Leach, MSS., p. 2. 



Shell conical, nearly smooth ; with six unequal valves, longi- 

 tudinally wrinkled, and very remote, nearly obsolete stria? on 

 the raised portions; aperture very large, extremely irregular on 

 the edge, internally striate transversely ; operculum abruptly 

 conical ; posterior valves with serrated external margins, and 

 striated transversely ; anterior valves with numerous, strong, 

 transverse ribs, which are crossed by many fine, longitudinal 

 striae, producing a decussated appearance, and with their inter- 

 nal margins serrated. 



Fig. 11, 12, the operculum. 



Fig. 8 is an elongated, cylindrical variety, found on the 

 Devonshire coast, by Dr. Leach. The species seems very 

 variable in form. 



This is the largest species of Balanus found in our seas, and 

 seems pretty widely diffused. Fig. 10 was found by W. C. 

 Trevelyan, Esq., at Hartlepool, adhering to a specimen of 

 Fusus antiquus. Fig. 9 was figured from a specimen in the 

 British Museum, and dredged in the Frith of Forth, where it 

 is not uncommon ; and I have lately procured some large and 

 beautiful specimens from the Irish coast. 



6. Balanus Scoticus, pi. LIII, f. 1,2, 3, and 22. 

 Balanus Scoticus, Wood, Gen. Conch., p. 40, pi. 6, f. 3. 

 Shell subconic ; surface divided into irregular, triangular 



compartments, obsoletely striated transversely; aperture large; 

 operculum triangular ; anterior valves with strong, transverse 

 striae ; posterior valves smooth, with greatly arcuated and sharp 

 points. 



Fig. 2, 3, the operculum. 



Found at Eyemouth, Frith of Forth, and at the mouth of 

 the Tay, adhering to muscles, stones, &c. 



7. Balanus punctatus, pi. LIII, f. 5, 6, 13, 20. 



Balanus punctatus, First Ed., pi. 7> f. 5, 6, 13, 20; Mon- 

 tagu, p. 8, pi. 1, f. 5; Fleming, Edin. Ency., p. 101 ; Brown, 

 Ency. Brit., VI, p. 402. 



Shell subconic, with indistinct compartments; generally with 

 numerous, longitudinal, narrow ribs, and several transverse lines 

 of growth; aperture wide, rather plain on the edge; operculum 

 somewhat depressed, with numerous punctures; front valves 

 finely striated transversely; posterior valves obtuse at the point, 

 with the front margins deeply indented. 



Fig. 5, 6, the operculum. 



Fig. 20, an elongated variety. 



Common on many of the British and Irish coasts, and is plen- 

 tiful on the rocks between Kinghorn and Kirkcaldy, Fifeshire. 

 2 H 



8. Balanus Cranchii, pi. LIII, f. 9, 10, 11, 12. 

 Balanus Cranchii, First Ed., pi. 7, f. 9, 10, 11, 12; Leach, 



Ency. Brit. Sup., Cirripedes, pi. 57 ; Lepas Cranchii, Brown, 

 Ency. Brit., VI, p. 403. 



Shell a depressed cone ; compartments indistinct ; sides 

 rounded, smooth, with numerous, longitudinal, frequently in- 

 terrupted stria?; basal margin extremely uneven; aperture very- 

 small, somewhat pyriform, and smooth at the edges; operculum 

 very large in proportion to the size of the aperture ; anterior 

 valves with strong, transverse striae in front, and becoming 

 arcuated posteriorly ; when separated, their internal margin is 

 found to be strongly serrated ; posterior valves striated trans- 

 versely, with greatly arcuated, sharp points ; external surface 

 of a reddish-purple, tinged with pale yellowish-buff, and with 

 from two to three transverse purple zones. 



Fig. 11, 12, the operculum. 



Common at Tenby, and other parts on the coast of Wales. 



9. Balanus conoides, pi. LIV, f. 7. 



Balanus conoides, First Ed., pi. 6, f. 7 ; Lepas conoides, 

 Donovan, I, pi. 30, f. 3; Montagu, p. 12; Fleming, Edin. 

 Ency., VII, p. 101 ; Maton and Rackett, p. 24. 



Shell conic ; valves pointed at the apex ; compartments ob- 

 scure, the three posterior ones larger than the others ; whole 

 surface longitudinally striated, and slightly so transversely, pro- 

 ducing a reticulated appearance, and of a pale reddish-purple 

 colour; aperture very small. Diameter at the base about 

 three-eighths of an inch. 



Found at Weymouth, by Mr. Bryer, attached to a specimen 

 of Pentelasmis Icevis. 



This is probably a foreign species. 



10. Balanus Montagui, pi. LIII, f. 24, 25, 26. 

 Acasta Montagui, First Ed., pi. 7, f. 24, 25, 26; Balanm 



spongeosus, Montagu, Sup., p. 2 ; Fleming, Edin. Ency., VII, 

 p. 101. 



Shell ovate ; with six angulated compartments, their points 

 extending considerably above the margin of the aperture ; 

 three anterior divisions broader and not so long as the 

 posterior ones ; external surface wrinkled, and provided with 

 numerous, spiniform processes ; operculum four-valved ; ante- 

 rior pair with strong, regular, deep, but narrow ridges, crossed 

 by longitudinal striae, producing a decussated aspect, internal 

 margins deeply serrated ; posterior pair larger than the others, 

 and with considerably arcuated, sharp points ; colour of a 

 livid or chocolate-brown. Length half an inch ; breadth some- 

 what less. 



Fig. 25, shell the natural size. 



Fig. 24, magnified. 



Fig. 26, the operculum. 



.Found embedded in sponge, at Portland Reach, by the late 

 Mr. Bryer, of Weymouth. 



11. Balanus spongicola, pi. LIII, f. 14, 15, 16. 

 Balanus spongicola, First Ed., pi. 7, f. 6, 14, 15 ; Leach, 



MSS., p. 1. 



Shell cylindrical ; with unequal compartments, the elevated 

 portion rising above the margin of the aperture, which is as 

 wide as the base of the shell ; operculum with four valves ; the 

 anterior ones with pretty strong, slightly oblique, transverse 

 stria?, and decussated by rather slender, waved, longitudinal 

 striae; posterior valves longitudinally striated, with considerably 



