278 ZOOPHYTES. 



in one or two cases detected a faint 'odour of 

 lemon ; but in most instances all sweet odour was 

 overpowered by the strong scent of burning bones, 

 or other animal substance, w^hich the hornwrack 

 gave out in the flame. This and the other horn- 

 wracks were formerly included under the name 

 of Sea-mat; hence Linnaeus gave the genus their 

 scientific name from the Saxon^wstfmm, ' to weave.'' 



The narrow-leaved Hornwrack (Flustra trun- 

 cata) mucli resembles this, but it is of a thinner and 

 more papery substance, and its segments are nar- 

 rower at the base. Though very common in deep 

 water on the Scottish coast, and on the northern 

 shores of England, it is less generally distributed 

 than the broad-leaved kind. Then there is a 

 pretty yellowish-brown species, called Flustra 

 carbasea, not uncommon on some coasts. The 

 polypes in this species have about twenty-two ten- 

 tacles, on which Dr. Grant remarks, " They are 

 nearly a third of the length of the body, and there 

 appears to be about 50 cilias on each side of a ten- 

 taculum, making 2,200 cilige on each polypus. 

 In this species there are more than 18 cells in a 

 square line, or 1,800, in a square inch of surface; 

 and the branches of an ordinary specimen present 

 about 10 square inches of surface, so that a com- 

 mon specimen of the Carbasea presents more than 

 18,000 polypi, 396,000 tentacula, and 39,600,000 

 cilias." 



Some sea-mats form patches on our common 

 marine plants, some inches in length, and they 

 may be seen by the naked eye to be composed of 

 a mass of cells. The membranous species (Flus- 

 tra membranacea], so common on the fronds of the 

 Laminaria, and different species of Fucus, forming 



