5 

 SPIRORBIS. 

 GENERIC CHARACTER: Tube testaceous, twisted into 

 a round flattened spire; lower surface flat, aud fixed to 

 another body. Operculum pedunculated, flat at the top, 

 situate between the branchiae. 



* SP. NAUTILOIDES. Serpula Spirorhis. Tart. Lin. 

 Pen. Brit. Zo., vol. 4, pi. 91, fig. 155. Stew. Elem., vol. 

 2, p. 422. Mont. Test. Brit., vol. 2, p. 498. Common on 

 stones, shells and other substanees. 



SP. SPIRILLUM. Serpula Sp. Turt. Lin. Stew. Elem., 

 vol. 2, p. 421. Mont. Test. Brit., vol. 2, p. 499. 

 Montagu says, this species has much the habit of the pre- 

 ceding, but is distinguished from it by its glossy appearance, 

 being more cylindric, and not spreading at the base. Com- 

 mon on shells, stones and other substances. 



* SP. GRANULATA. Serpula G. and Sulcata. Turt. 

 Lin. Mont. Test. Brit., vol. 2, p. 500. Common on rocks 

 and stones. 



* SP. CARINATA. Serpula C. Mont. Test. Brit., vol. 2, 

 p. 502. It is distinguished from Sp. Nautiloides by the 

 angulated shape of the outer whirl, which is formed like 

 that of Vermilia Triquetra, but regularly spiral. Not 

 uncommon on shells. 



* SP. CORRUGATA. Serpula C. Mont. Test. Brit., 



vol. 2, p. 502. Not uncommon. 



* SP. MINUTA. Serpula M. Mont, Test. Brit., vol. 2, 

 p. 505. 



Montagu observes, this very minute species is also an 

 heteroclitical shell, and not easily distinguished from S. He- 

 terostropha, except by its inferior size, and habits; this 

 affects only the Corallina officinalis, frequently in abundance, 

 both on stalks and branches. 

 SP. LUCIDA. Serpula Reflexa and S. Vitrea. Turt. Lin. 



S. L. Mont. Test. Brit., vol. 2, p. 507. 



Montagu says, it is peculiar to some species of Sertularia, 

 especially S, Abietina and S. Argentea ; and on them not 

 uncommon. 



SERPULA. 

 GENERIC CHARACTER: Tube testaceous, creeping, 



tapering, irregularly twisted, sometimes slightly keeled ; 



fixed to another body. 



* S. VERMICULARIS, S. Intricata. Turt. Lin. Pen. 

 Brit. Zo., vol. 4, pi. 91, fig. misplaced, 158. Stew. Elem., 

 vol. 2, p. 422. Mont. Test. Brit., vol. 2, p. 509. Common. 



* S. TUBULARIA. Mont. Test. Brit., vol. 2, p. 513. The 

 most beautiful, and commonly the largest, of the British 

 Ssrpulaeas. It comes from deep water, and is scarcely 

 common. 



