20 



cells by short peduncles. In the summer and autumn they 

 are plentifully produced on all parts of the polypidom. The 

 polype is granular, with fourteen stout tentacula; and when 

 in activity, protrudes itself about the length of the cell 

 beyond the aperture. The life of this species can be but of 

 short duration. When growing on fuci, it is destroyed by 

 the waves tearing these fuci from the rocks; and when it 

 fixes itself on the rocks, it soon becomes infested with minute 

 sponges and convervae which grow over the apertures of 

 the cells and prevent the polypes from having access to the 

 water; whereby they perish. It is also much infested with 

 minute insects ( entomastraca ) of the genus Cyclops, which 

 is probably the cause of the light so frequently given off 

 when this species is gently struck while in the water. 



SERTULARIA PINNATA. Cells opposite, tubular, the 

 upper part free and divergent, with an even patulous 

 aperture; vesicles obconical, trituberculate on the top. 



Sertularia Pinnata, Johnston's Brit. Zooph., p. 127, pi. ix, 

 fig. 5 and 6* Sertularia Fuscescens, Turton's Lin., vol. 4, 

 p. 677. Lamouroux's Cor. Flex., p. 195. Dynamena 

 Pinnata, Fleming's Brit. An., p. 545. 



Hab. " Oceanus ad Prom. Lacertae, Cornubiaa," Pallas. 

 I have not met with a specimen, and it is therefore called 

 Cornish on the authority of Pallas. 



BLACK CORALLINE. S. Nigra. Cells very nearly 

 opposite, approximated, appressed, small ovato tubular, 

 apertures even and not everted; vesicles like an unripe 

 fig, with small contracted terminal apertures. 



Sertularia Nigra, Turton's Lin., vol. 4, p. 676. John- 

 ston's Brit. Zooph., p. 128, fig. 15, p. 129, and fig. 13, p. 119. 

 MantelPs "Wonders of Geology, vol. 2, p. 534. Dynamena 

 Nigra, Fleming's Brit. An., p. 545. 



Hab. Lizard point, Pallas; off Polperro and Deadman 

 point; not uncommon. 



This species varies from three to six inches and sometimes 

 even to eight inches in height. The trunk and pinnae are 

 stout, rigid, and divided into joints at regular intervals. The 

 pinnae arise from the trunk alternately, and very close to each 

 other. The cells are arranged in a bi-serial manner, on the 

 pinnae and trunk ; they are semialternate, crowded, and 

 adnate or pressed against the polypidom ; they are tubular, 

 with even patulous apertures; on the lower part of the trunk 

 they are generally absent, but are always to be found on 

 the upper and newer portions. The vesicles, in shape, 

 resembling unripe figs, are attached to the polypidom by 



