Serpulacea.] 



MOLLUSCA. 



123 



Section II. — Shells attached to extraneous bodies nearly 

 their whole length. 



5. Serpula triquetra, pi. LV, f. 1,5. 



Serpida triquetra, First Ed., pi. 2, f. 1, 5 ; Pennant, IV, p. 

 146, pi. 91, f. 157; Donovan, pi. 95; Montagu, p. 511 ; Maton 

 and Rackett, p. 244 ; Fleming, Edin. Ency., VII, p. 67- 



Tube adhering its whole length, strong, opaque, irregularly 

 contorted; sometimes nearly straight, or slightly flexous; with 

 transverse wrinkles, and provided with a central dorsal carina, 

 which in some instances becomes nearly obsolete at the larger 

 end of the tube ; in some specimens the ridge is elevated, and 

 in others depressed; spreading widely at the base; aperture 

 subtriangular ; colour yellowish-white, sometimes of a fine red, 

 orange, citron, or rose-colour. 



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

 old shells, stones, &c. 



6. Serpula vermicularis, pi. LV, f. 2, 3. 



Serpula vermicularis, First Ed., pi. 2, f. 2, 3 ; Pennant, p. 

 146, pi. 91, f. 158; Montagu, p. 509 ; Maton and Rackett, p. 

 240; Brown, Ency. Edinensis, II, p. 556, pi. 55, f. 12; lb., 

 Ency. Brit., VI, p. 468. 



Tube strong, adhering its whole length, cylindrical, white, 

 transversely wrinkled, contorted in various directions, tapering 

 gradually to a fine point ; aperture circular. 



Common on most of the British and Irish coasts. 



7. Serpula serrulata, pi. LV, f. 8. 



Serpula serrulata, First Ed., pi. 2, f. 8 ; Fleming, Edin. 

 Ency., VII, p. 67, pi. 204, f. 8. 



Tube bluish-white, smooth, glossy, diaphanous, adhering, 

 subtriangular, slightly contorted ; base spreading pretty widely, 

 tapering rather abruptly to a fine point ; back with an elevated, 

 thin, sharp ridge, finely but irregularly serrated, and equal in 

 dimensions to the breadth of the tube ; aperture large, nearly 

 orbicular, with the tooth-like termination of the carina project- 

 ing over it. 



Discovered by Dr. Fleming, in deep water, adhering to 

 stones, on the coast of Zetland ; and I found it plentiful in 

 Rothesay Bay, in company with my friend James Smith, Esq., 

 of Jordan Hill, near Glasgow, while on a dredging excursion. 



The shell is so transparent, that the animal can be distinctly 

 seen through it ; and by the aid of a strong lens the pulsation 

 may be observed. 



Genus 2 — Spirorbis Lamarck. 



Shell consisting of a testaceous tube, spirally twisted into an 

 orbicular form on a horizontal plane, depressed, and adhering 

 below ; the aperture terminal, rounded, or angular. 



1. Spirorbis Nautiloides, pi. LVI, f. 45. 



Spirorbis Nautiloides, First Ed., pi. 1 , f. 45 ; Lamarck, V, p. 

 359 ; Serpula spirorbis, Donovan, I, pi. 9, f. 1,2; Montagu, 

 p. 498; Maton and Rackett, p. 241. 



Shell opaque, white, much depressed ; with three or four 

 lateral volutions, rounded above, and slightly wrinkled trans- 

 versely ; the central volution lower than the others, and 

 forming an umbilicus ; base flat, and expanded ; aperture sub- 

 triangular. 



Common on most of the British and Irish coasts, adhering 

 to algce and other marine plants, as well as to stones and 

 shells. 



A lusus of this shell is not unfrequent with an erect aperture, 

 and one or two volutions turning a little spirally upwards. 



2. Spirorbis spirillum, pi. LVI, f. 41, 42, 53, 54. 

 Spirorbis spirillum, First Ed., pi. 1, f. 41, 42, 53, 54; 



Lamarck, V, p. 359 ; Fleming, Edin. Ency., VII, p. 68 ; Ser- 

 pula spirillum, Montagu, p. 499 ; Pulteney, Hutch. Dorset, p. 

 52, pi. 19, f. 27 ; Maton and Rackett, p. 240. 



Shell subdepressed, subpellucid, glossv, white ; with two or 

 three subcyliudrical, slightly wrinkled, somewhat lateral volu- 

 tions ; central volution lower than the others, forming an um- 

 bilicus, and pervious in some instances ; aperture subtriangular, 

 and not unfrequently turned upwards ; attached by the smaller 

 end. Diameter not more than an eighth of an inch. 



Fig. 53, 54, var., Spirorbis sinistrosa, Montagu, p. 504. 



Sometimes the volutions wind spirally upon each other. 



Distinguished from S. Nautiloides by its glossy aspect, its 

 more cylindrical form, and not spreading at the base. 



Generally found adhering to marine plants, corallines, and 

 Crustacea, and not to stones. 



3. Spirorbis minutus, pi. LVI, f. 51. 



Spirorbis minutus, First Ed., pi. 1, f. 51 ; Fleming, Edin. 

 Ency., VII, p. 68, pi. 205, f. 2 ; Serpula minula, Montagu, p. 

 505 ; Maton and Rackett, p. 241. 



Shell heteroclitical, depressed, yellowish-white ; with two or 

 three lateral, transversely wrinkled volutions, and a dorsal 

 carina. Diameter a quarter of a line. 



Found adhering to corallines, on the Devonshire and Nor- 

 thumberland coasts. 



4. Spirorbis heterostrophus, pi. LVI, f. 55. 

 Spirorbis heterostrophus, First Ed., pi. 1, f. 55; Fleming, 



Edin. Ency., VII, p. 68, pi. 205, f. 1 ; Serpula heterostropha, 

 Montagu, p. 503 ; Maton and Rackett, p. 242. 



Shell strong, dull white; consisting of two or three hetero- 

 clitical volutions, with three lateral, spiral ridges, crossed by 

 strong wrinkles ; base flat, somewhat spreading ; aperture orbi- 

 cular. Diameter not a line. 



Found adhering to oysters and other shells, and to algce, on 

 many of the British and Irish coasts. 



5. Spirorbis heterocliticus, pi. LVI, f. 57- 

 Spirorbis heterocliticus, First Ed., pi. 1, f. 57. 



Shell nearly cylindrical, thick, white, opaque, smooth ; with 

 four volutions, the outer one very large, internal ones small, 

 forming a large and deep umbilicus ; aperture nearly orbicular, 

 and placed below the margin of the outer volution. Diameter 

 one-tenth of an inch. 



Found by my late friend General Bingham, adhering to the 

 roots of algce, at Dunbar. 



6. Spirorbis granulatus, pi. LVI, f. 47. 



Spirorbis granulatus, First Ed., pi. 1, f. 47; Fleming, Edin. 

 Ency., VII, p. 68 ; Serpula granulata, Montagu, p. 500 ; 

 Donovan, III, pi. 100. 



Shell subdepressed, white, opaque; with two volutions, deeply 

 grooved spirally, and transversely wrinkled, more strongly so in 

 the furrows, umbilicated ; aperture orbicular, with an annular 

 tip. Diameter an eighth of an inch. 



