NATURE STUDY IN SCHOOLS. 141 



Now to return to our Laminaria ; as shown, this is an embassidor, per- 

 haps an unwilling one, from a deep water region known, from the abun- 

 dance of this kind of sea- weed there, as in the laminarian zone, hence we 

 may judge that it has brought with it some examples of animal life that 

 occur there. Knowing this, then, let us look more carefully at the object to 

 which the roots of the plant are clinging. 



Upon examining the object in question, we find that it is a large shell 

 nearly six inches long, of a rich chestnut brown color, and by removing the 

 roots, as I have termed the small divisions of the stem of the sea-weed by 

 which it is fastened to the shell, but rather improperly, for strictly speaking 

 they are not roots, but cables, for all the sea- weeds derive their nourishment 

 from the atmosphere or water, and this is applied through the entire surface 

 of the plant ; I say by removing these cables we can better examine the 

 shell. We find that the side to which the attachment was made is consid- 

 erably curved, but the lower side is straight. From this lower side, near the 

 small end, are a large number of threads, or rather something that closely 

 resembles quite coarse black thread. This is known as the byssus and at 

 once tells us that the shell is a species of mussel. This is true, it is the 

 horse-mussel, Modiola modiolus, and inhabits deep waters. 



The byssus serves as a cable, and in turn anchors the shell to the bot- 

 tom ; this cable must be exceedingly strong to hold the large sea- weed in po- 

 sition, yet this laminaria is small ; I have seen specimens, also attached to 

 shells, that were twenty feet long, and some occur that are longer. These 

 seem large for plants, but they are small compared to those which grow in 

 other parts of the world ; thus we have a British species that grows forty 

 feet in length and this is a dwarf in comparison to a South Atlantic sea- 

 weed that attains the altitude of three hundred feet ; this in turn falls into 

 comparative insignificance beside a Pacific Ocean species that trails its enor- 

 mous length over a thousand feet of water, or, according to some authors, 

 grows to be fifteen hundred feet long. Where are the various forest trees 

 of land beside this vegetable product of the ocean? Even the giant red- 

 woods of California must lower their diminished heads before this tower- 

 ing sea plant. 



But what is this singular animal that has fallen out of the sea- weed? 

 It is another member of the moluska, or a mollusk. I hear some one ex- 

 claim, who looks at the cut which is here given, " I thought mollusks were 

 shells." So they are shells, so to speak, as a rule, or better they carry 

 shells, in nearly all species, on the outside of their bodies, but this squid 

 or cuttle fish carries its shell within its body. Not all of this group are 

 unprovided with external shells, for the various species of nautalus, which 



