9 



fragments of bivalves (chiefly Pectens) which are irregu- 

 larly disposed, often imbricated, but invariably with the 

 concave side outwards, which leaves a narrow perfora- 

 tion. Torcross, Devonshire, in deep water. 



TRIBE. SERPULACE^E. 

 Tube solid and calcareous. 



GENUS. SPIRORBIS. 

 Tube testaceous, twisted into a spiral discoid orb ; 



lower surface fiat and affixed. 



S. NAUTILOIDES. Lam. 1. SERPULA SPIRORBIS. 

 Lin. 1265. List. t. 553. /. 6. Mart. f. 21. A. B. 

 Pen. 4. p. 145. t. 21. /. 155. Da. Cost. t. 2. /. 

 \\.-Mont.p. 498. D! p. \Q73.-Turt. D. p. 149. 

 Don. t. 9. Opaque, white, with three or four regular 

 lateral whorls, rounded on the upper part and a little 

 wrinkled; umbilicated in the centre; base flat, spread- 

 ing. Variety. With the mouth erect and sometimes a 

 whorl or two turning a little spirally upwards, $. 

 Excessively common on lobsters, fyc. 



S. SPIRILLUM. Lam. 2. SERPULA. S. Lin. 1264. 

 Turt.D.p.l50.Dor. Cat.t. 19. /. 27. D. p. 1072 

 Mont. p. 499. -Zz'w. T. S. p. 240. Reversed var. 

 SINISTORSA. Mont. p. 504. Walk. f. 134. Glossy 

 white, semi-transparent, orbicular, regular ; whorls two or 

 three, slightly wrinkled, and mostly placed laterally, the 



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