238 



SERTULARIID^E. 



the aperture and the base, somewhat compressed, strongly 

 ringed above, the lower portion smooth aperture small, 

 with two denticles. 



THE S. Gayi of Lamouroux was regarded by Dr. Johnston 

 as a variety of the somewhat protean S. polyzonias ; but 

 after some consideration, I venture to restore it to specific 

 rank. In habit it is sufficiently distinct. The stems are 

 thick and coarse, made up of many fibres agglutinated 

 together, erect, and rigid, and wanting altogether the sub- 

 flexuous character of the allied species. They are pinnate, 

 the pinme springing alternately at regular intervals and 

 very close together, whereas in S. polyzonias the branches 

 are distant and irregularly distributed. The calycles differ 

 but slightly in the two species. Those of S. Gayi are 

 somewhat stouter, and frequently wrinkled transversely. 

 The capsules afford a good specific character. They are 

 rather smaller and more slender than those of polyzonias, 

 compressed, tapering very decidedly towards the apex, 

 and wanting the tubular orifice (Woodcut, fig. 29). The 



Fig. 29. 



aperture is smaller, and bears only two opposite denticles 



