71 



MOLLUSCA. 



[Malleacea. 



Genus 6. — Lima. — Bruguiere. 



Shell longitudinal, equivalve, inequilateral ; sides somewhat 

 thickened, and gaping; unibones divergent, their internal facets 

 inclined outwards ; hinge provided with two lateral teeth, one 

 on each side in both valves, which become nearly obsolete in 

 adult shells ; area between the beaks to which the ligament is 

 attached, tripartite; the middle or hinge pit rounded above, and 

 contains the chief portion of the ligament, the remaining por- 

 tions are attached to the somewhat elongated linear divisions ; 

 muscular impression lateral, suborbicular, from the inner mar- 

 gin of which the muscular impression of the mantle emanates, 

 and traversing the outside of the valves in a circuitous form, 

 appears to terminate near the beak ; external surface covered 

 with a very thin epidermis. 



1. Lima sulcata, pi. XXIII, f. 4, 5. 



Lima sulcata, First Ed., pi. 31, f. 4, 5; Leach, MSS., p. 11 ; 

 Lima subauricularia, Fleming, p. 388 ; Turton, Biv., p. 218 ; 

 Pccten subauricularia, Montagu, Sup., p. 63. 



Shell white, pellucid, oblong-ovate, equilateral, and equivalve ; 

 provided with small angular auricles; whole surface covered with 

 numerous, longitudinal, divergent striae, with two opaque, cen- 

 tral, rib-like projections emanating from the umbones, and ter- 

 minating on the margins, which are crenated ; inside smooth, 

 glossy, with indications of the two external ribs. Length up- 

 wards of three-eighths; breadth half its length. 



First discovered on the Devonshire coast, and has been met 

 with in the Frith of Forth and Zetland. 



A variety of this shell was found in sand, south of Bute, by 

 Stewart Ker, Esq., in which the two elevated central striae are 

 not so conspicuous, but are indicated internally ; it also differs 

 in all the striae on the sides having intermediate ones, which are 

 less elevated than the others. 



2. Lima fragilis, pi. XXIII, f. 6, 7, 7.* 



Lima fragilis, First Ed., pi. 3 1 , f. 6, 7 ; Lamarck, VI, p. 1 57 ; 

 Fleming, p. 388; Forbes, p. 40; Lima bullata, Turton, p. 217, 

 pi. 17, f. 4, 5; Lima Goodallii, Leach, MSS., p. 11 ; Pecten 

 fragilis, Montagu, Sup., p. 62 ; Brown, Ency. Brit., p. 418. 



Shell subovate, very convex, fragile, white, subpellucid ; valves 

 equal, inequilateral, one side straight, the other arcuated, nearly 

 closed on all sides, with numerous, slightly undulating, longitu- 

 dinal stria?, and with two or three minute, fine, intermediate 

 ones ; auricles small, oblique ; umbo prominent, small, and 

 straight, the beaks distant ; inside smooth, shining, and white ; 

 hinge line a little oblique. Length upwards of three-quarters 

 of an inch ; breadth not quite half an inch. 



Found on the Devonshire and Manx coasts; and at Bute and 

 Frith of Forth, Scotland. 



3. Lima tenera, pi. XXIII, f. 8, 9. 



Lima tenera, First Ed., pi. 31, f. 8, 9; Turton, Zool. Joum., 

 II, p. 362, pi. 13, f. 2; Forbes, p. 41 ; lb., Mag. Nat. Hist., V, 

 p. 594, f. 64. 



Shell compressed, inequilateral, gaping at both sides; anterior 

 side somewhat triangular, with the opening margined internally, 

 with a strong rounded rib ; external surface furnished with 

 twenty-live somewhat undulated, nearly smooth ribs; margin 

 serrated ; hinge line oblique. 



This species is much stronger than the L. fragilis. 



First found in the British Channel, by Dr. Turton ; Forbes 



found it on the Manx coast ; and it was detected at Lamlash 

 Bay, Arran, by James Smith, Esq., of Jordan Hill. 



4. Lima vitrina, pi. XXIII, f. 10, 10,* 11, 11.* 

 Lima vitrina, First Ed., pi. 31, f. 10, 11. 



Shell oblong-ovate, convex, very fragile, white, and subpellu- 

 cid ; hinge line very oblique, with a large triangular pit for the 

 accommodation of the cartilage socket ; umbo small, and much 

 turned to one side; whole shell considerably twisted; the valves 

 gaping on both sides, with numerous, slightly undulated, notch- 

 ed, divergent stria;, crossed by exceedingly fine, undulating, 

 concentric striae, not discoverable without the aid of a lens, and 

 with many, nearly obsolete, concentric wrinkles ; auricles small, 

 slightly striated transversely ; inside clear white, and very glossy. 

 Length nearly an inch and a half; breadth about an inch. 



I found one valve of this at Ballantrae, Ayrshire ; and it was 

 afterwards met with on the Argyleshire coast, by Captain Car- 

 michael ; and Mr. Stewart Ker found it on the shores of the 

 Island of Bute. 



5. Lima inflata? 



Lima inflata ? Forbes, Mag. Nat. Hist., V, p. 593, f. 63 ; lb., 

 Mai. Mon., p. 41 ; Lamarck, VI, p. 156? 



" Shell strong, inflated with rough longitudinal ribs, crossed 

 by lines and furrows of growth ; gaping on all sides widely. 

 Dimensions, length fourteen-tenths; breadth nine-tenths; thick- 

 ness nine-tenths." 



Dredged in deep water off the Manx coast, by Professor 

 Forbes. 



Section III Ligament marginal, elongated. 



Family I Malleacea. 



Shells foliaceous, more or less inequivalve, with a marginal 

 ligament, which is partly linear, and simple, or interrupted by 

 crenulations. 



Genus 7- — Avicula. — Lamarck. 



Shell inequilateral, inequivalve, foliaceous, subquadrate, and 

 oblique; pearlaceous within; hinge rectilinear, and produced on 

 each side into rectilinear appendages, with a small, indistinct 

 tooth in both valves; an elongated, marginal, ligamentiferous 

 area, widened near its centre. 



1. Avicula Anglica, pi. XXIII, f. 3. 



Avicula Anglica, First Ed., pi. 31, f. 3; Leach, MSS., p. 1 1. 



Shell very thin, with the hinge line but slightly bent ; cardi- 

 nal lobe short, and acute above; posterior lobe rather long; 

 whole surface concentrically wrinkled, with imbricated, nearly 

 equidistant, scale-like spines, running in transverse series ; out- 

 side fawn-coloured, with interrupted, longitudinal streaks of 

 umber-brown, becoming iridescent towards the base, besides the 

 scales, which are attached to the elevated stria:; at regular inter- 

 vals it is provided with long, sharp spines, of a yellowish-brown 

 colour, which lie close to the shell. 



Discovered on the Devonshire coast, by Dr. Leach. 



2. Avicula Atlantica, pi. XLVI, f. 6, 7- 



Avicula Atlantica, First Ed., pi. 10,* f . 6 ; Lamarck, VI, p. 

 148 ; Avicula hirundo, Turton, Biv., p. 220, pi. 17, f. 3 ; Fle- 

 ming, p. 405 ; Mytilus hirundo, Turton, Conch. Diet., p. 101, 

 pi. 1, f. 7. 



