Pedunculata.] 



MOLLUSCA. 



119 



Genus 4. — Scalpellum. — Leach. 



Shell laterally compressed, subquadrate, acuminated above ; 

 and composed of thirteen valves, one pair acuminated and 

 apicial, another pair ventral, two pair lateral, and an arcuated 

 one on the back; attached to extraneous substances by a short, 

 scaly, or hairy peduncle. 



1. Scalpellum vulgake, pi. LI, f. 1, 9, 10. 

 Sculpellum vulgare, First Ed., pi. 5, f. 7, 9, 10; Leach, 



Ency. Brit. Sup., Cirripedes, pi. 57 ; lb., MSS., p. 1 ; Pol- 

 licipes scalpellum, Lamarck, V, p. 407 ; Brown, Ency. Brit., 

 VI, p. 403. 



Peduncle horn-coloured, scaly, attenuated below, and covered 

 with smooth scales ; shell compressed, provided with thirteen 

 horn-coloured valves, with obsolete stria?. 



Found on many of the British and Irish coasts, adhering to 

 rotten timber, &c. 



Variety a, f. 7. Valves close, strongly striated concentri- 

 cally ; peduncle with the scales set in regular rows. 



Scalpellum vulgare, Leach, Ency. Brit. Sup., pi. 57. 



Variety b, f. 9- Valves considerably apart, substriated con- 

 centrically ; peduncle with close-set, imbricated scales. 



In Lady Jardine's cabinet. 



Variety c. Valves all separated, and concentrically substri- 

 ated ; side valves with a central, projecting point ; peduncle 

 with the scales set in regular annulations. 



Donovan, pi. 166, f. 1. 



2. Scalpellum smilium, pi. LI, f. 8. 



Scalpellum vulgare, First Ed., pi. 5, f. 8; Smilium Peronii, 

 Sowerby, Conch. Man., p. 260, pi. 2, f. 36 ; Lepas scalpelhim, 

 Montagu, p. 18, pi. 1, f. 4. 



Shell consisting of thirteen smooth, light brown valves, ten of 

 them in pairs, placed laterally, and subtriangular ; one situated 

 posteriorly ; peduncle with annular, scaly processes, slightly 

 imbricated, and beset with numerous, fine, short hairs. 



Found at Sandwich and Plymouth, in deep water. 



Genus 5 Pentelasmis. — Leach. 



Shell laterally compressed, conical, and composed of five 

 valves, held together by a membraneous, ligamentary process ; 

 lower valves the largest, of a subtrigonal form, a little convex, 

 and acute at their anterior base; upper lateral pair elongated, 

 and subquadrate, dorsal one lanceolate, carinated, and arcuated ; 

 seated on a peduncle, which is of variable length. 



1. Pentelasmis anseriferus, pi. LI, f. 1. 



Anatifa striata, First Ed., pi. 5, f. 1 ; Lepas anseriferus, 

 Montagu, p. 16; Donovan, pi. 166; Maton and Rackett, 

 p. 28. 



Shell compressed, bluish-white, and glossy ; larger valves 

 somewhat inflated behind ; four of them with strong, radiating 

 striae, assuming the character of furrows towards the margins of 

 the valves, which are crossed by very fine striae, giving them a 

 faint reticulated appearance ; angles of the valves sharp, espe- 

 cially the apicial one; dorsal valve compressed at the sides, and 

 brought to a fine carinated margin ; superior valves much com- 

 pressed, rendering the shell extremely thin and flat on the pos- 

 terior side. Length an inch ; breadth three-quarters. 



Found on drifted wood, on several of the British and Irish 

 coasts. 



2. Pentelasmis stiatus, pi. LI, f. 4, 5, 6. 



Anatifa striata, First Ed., pi. 5, f. 4, 5, 6 ; Lepas sulcata, 

 Montagu, p. 17, pi. 1, f. 6j Maton and Rackett, p. 29. 



Shell compressed, subtriangular ; the inferior valves with fif- 

 teen strong ribs, diverging from the lower anterior angle ; that 

 which runs along the front is larger than the others, and forms 

 a margin ; the two superior valves terminating above in an 

 acutely pointed apex ; with seven or eight ribs, and smaller 

 intermediate ones, diverging from the posterior margin; dorsal 

 valve somewhat compressed, with strong, longitudinal strias, and 

 a smooth, subcarinated edge; colour yellowish-white; peduncle 

 short, dusky. Length a quarter of an inch; breadth nearlv 

 the same. 



Found attached to Gorgonia jlabellum, on the Dorsetshire 

 coast, near Portland Island. 



Variety b, f. 5, 6. 



Lepas striata, Wood, Gen. Conch., p. 164, pi. 10, f. 5; 

 Leach, Ency. Brit. Sup., Cirripedes, pi. 57; Pentelasmis pumi- 

 cicola, Leach, MSS., p. 1 . 



Found on many of the coasts of Britain and Ireland, attach- 

 ed in clusters to rotten wood, stones, &c. Montagu mentions 

 its having been found on Gorgonia jlabellum, near Portland 

 Island. 



3. Pentelasmis anatiferus, pi. LII, f. 1, 2, 3, 4. 

 Anatifa Lcevis, First Ed., pi. 4, f. 1, 2, 3, 4 ; Lamarck, V, 



p. 404 ; Pentelasmis anatifera, Leach, MSS., p. 1 ; Lep>as ana- 

 tifera, Pennant, IV, p. 74, pi. 38, f. 9 ; Donovan, I, pi. 7 ; 

 Montagu, p. 15 ; Maton and Rackett, p. 28. 



Shell compressed, of a bluish-white, and very glossy ; two 

 lower valves somewhat triangular, longitudinally wrinkled, with 

 nearly obsolete stria;, radiating from the lower interior angle ; 

 two superior valves elongated, and tapering to an obtuse point, 

 upper portion angulated on both sides, apex rounded, these 

 have likewise obsolete, radiating striae, and are longitudinally 

 wrinkled from the upper posterior angle ; dorsal valve long, 

 slender, arcuated, smooth down the middle, and sulcated on 

 the sides; connecting cartilage and peduncle of a reddish- 

 orange, frequently inclining to scarlet, the latter extremelv 

 variable in length, as will be seen from the different specimens 

 figured ; in a solitary instance, we met with it of a pale brown, 

 as in fig. 1. 



Found attached to pieces of rotten wood, on many of the 

 British and Irish coasts, and is the most common species of the 

 genus. 



Fig. 2 and 4, the more ordinary form of the species. 



Fig. 1, more dilated, the dorsal valve appearing as if jointed. 



Fig. 3, a rare variety, with the larger valves more dilated than 

 usual, and with strong stris. In the cabinet of Mr. Albany 

 Hancock, Newcastle-upon-Tyne. 



4. Pentelasmis dentatus, pi. LII, f. 5. 



Anatifa dentata, First Ed., pi. 4, f. 5 ; Lamarck, V, p. 405 ; 

 Bruguiere, Diet., No. 3 ; Lepas dentata, Dillwyn, Cat., p. 32. 



Shell with very smooth, glossy valves, of a bluish-white ; 

 aoreeing in every particular with those of P. anatiferus, 

 excepting the dorsal valve, which is provided with a series of 

 oblique, saw-like teeth ; peduncle short, and of a pale scarlet 

 colour. 



