SERTULARIAD,E. 361 



is affixed by a horny, branching, interlacing, tubular fibre 

 to the object on which it grows. At different parts there 

 are plumous shoots, usually about an inch in height. The 

 cells are of a yellow colour, set in the stalk, of a bell- 

 shape, and are compared to the flower of the lily of the 

 valley ; the rim is cut into eight equal teeth ; the polype 

 minute and delicate, tentacles ten and annulate, with a 

 mouth infundibuliform in shape. 



" Each plume," says Mr. Lister, in reference to a speci- 

 men of this species, "might comprise from 400 to 500 

 polypes ;" " and a specimen," writes Dr. Johnston, " of no 

 unusual size, before me, has twelve plumes, with certainly 

 not fewer cells on each than the larger number mentioned : 

 thus giving 6000 polypes as the tenantry of a single poly- 

 pidom ! Now, many such specimens, all united too by a 

 common fibre, and all the offshoots of one common parent, 

 are often located on one sea- weed, the site then of a popu- 

 lation which nor London nor Pekin can rival." 



Plumularia pinnata, " Feather polyp," (represented mag- 

 nified in fig. 192, No. 1,) is as remarkable for the ele- 

 gance of its form, as its likeness to the feather of a pen. 

 It serves not among the denizens of the deep the same 

 purpose as its earthly prototype ; nature writes her 

 works in hieroglyphics formed by the objects themselves. 

 It is plumous, and the cells in a close row, cup-like, 

 and supported on the under side by a lengthened spinous 

 process. 



An interest pervades the valuable work of Dr. Johnston, 

 arising from the circumstance that the plates and wood- 

 cuts which adorn the volume are, with few exceptions, 

 engraved from drawings made for it by Mrs. Johnston, 

 who also engraved several of them ; and the Doctor states, 

 he could not have undertaken the history without such 

 assistance. From this devotion too, and understanding of 

 the subject, it was natural, when an opportunity presented 

 itself, to write in the catalogue of Zoophytes a lasting 

 memorial of his " colleague :" and thus is written the 

 graceful compliment of the beautiful Plumularia Catha- 

 rina : " Catharine's Feather," whose stem is plumous, pinnae 

 opposite, bent inwards; cells distant, campanulate, with 

 an even margin ; vesicles scattered, pear-shaped, smooth. 



