186 Objects for the Microscope. 



Ptilota is a perennial plant found in summer and autumn 

 frequently growing on the stems of Laminaria digitata, and 

 therefore our best specimens may be gathered on the beach 

 after the autumnal equinoctial gales. At Torquay it is 

 found on rocks, but Ptilota sericea is often mistaken for it ; 

 this is very abundant on the rocks at Moulin Huet in 

 Guernsey, hanging in rich silky masses on the sheltered 

 side of the rocks, and thronged with that minute but lovely 

 zoophyte Eucratia chelata. 



PLOCAMIUM VULGARE, OR COCCINEUM. 



Plocamium coccinewn it is called from its fine crimson 

 colour, and the word Plocamium means, in Greek, " braided 

 hair," which the fine divisions of the frond resemble. 



A small branch of this lovely weed has been thus hap- 

 pily described in a French botanical work, and will direct 

 the eye in examining this slide. I shall therefore tran- 

 scribe it : 



" Sa tige est tres-rameuse, et toujours dans le meme 

 plan ; Pordre des ramifications est tres-remarquable ; chaque 

 rameau est legerement flexueux, et n'emet de ramifications 

 que du cote convexe : la premiere est un filet simple et 

 pointu ; la deuxieme est tin filet qui a trois dents du cote 

 anterieur ; la troisieme est un filet qui a deux dents, et qui 

 au lieu de la troisieme dent pousse un filet muni d'une dent 

 en dehors ; la quatrieme est un filet qui n'a qu'une dent, la 

 deuxieme dent est devenue tine filet a une dent, et la 

 troisieme un filet rameux. 



" Apres ces quatre ramifications il y a une espace vide, 

 et la tige emet des rameux semblables du cote oppose." 



The fructification is of two kinds : 



1. The stichidia, or oblong vesicles containing spores in 

 separate divisions or cells very beautiful. 



2. Spherical capsules, seated upon the branches, contain- 

 ing a cluster of spores. 



This is a common Sea-weed everywhere in summer and 

 autumn. 



POLYSIPHONIA. 



There are twenty-four species of this Sea-weed, some of 



