Algal.s.] 



CONFERVACEyE. 



Fig. YU. 



examined by Dr. Uuger. When arrived at its full growth, it consists of transparent 

 threads of extreme fineness, packed together as closely as the pile of velvet ; they 

 greatly resemble, in general appearance, certain kinds of mouldiness. These threads 

 ai*e terminated by an extremity about -j^ o ^^ ^^ ^^^^^^ ^^ diameter, consisting of a long 

 single cell, within which is collected some green mucilage intermixed with granules. 

 Dr. Unger assiu'es us that at this 

 time ro starch is present, but the 

 whole of the green matter is of the 

 nature of gum, as is proved by the 

 action of iodine upon it. The con- 

 tents of the cell are seen to be in 

 constant motion, dii-ectiug them- 

 selves in lines such as are repre- 

 sented at Fig. 5. While this is 

 going on, the end of the cell con- 

 tinues to grow, and at the same 

 time the contents collect at the 

 extremity, and distend it into a 

 small head in form resembling a 

 club, immediately after which a 

 chamber is formed, and then the 

 first stage of fructification is ac- 

 complished. The next change is 

 observed to take place in the gra- 

 nular matter of the clubhead, which 

 itself enlarges, while the contents 

 gain opaqueness, and by degrees 

 arrange themselves in five or six- 

 sided meshes, which are in reality 

 the sides of angular bodies, that 

 are rapidly forming at the expense 

 of the mucilage above mentioned, 

 which has disappeared. It is not the least sm'prising part of this history, that all the 

 changes above mentioned take place in the course of an hour or an hour and a half, so that 

 a patient observer may actually witness the creation of this singular plant. At this time 

 all the v-ital energy seems directed towards changing the angular bodies in the inside of 

 the clubhead into propagating germs or spores. Aleanwhile the clubhead grows, and 

 gives them a Httle room, and they in their turn alter their form and become oval. 

 Then it is that is witnessed the surprising phenomenon of spontaneous motion in the 

 spores, which, notwithstanding the narrow space in which they are born, act with such 

 vigour that at last they force a way through the end of the clubhead. At first one 

 spore gets out into the water, then another, and another, till at last the clubhead is 

 emptied. All this takes place v.ith such rapidity that a minute or two suffice for the 

 complete evacuation of the clubhead or spore-chamber. The spores, when they find 

 their way into the water, are generally egg-shaped, and swim luith their small end fore- 

 most ; but they are often deformed, in consequence of the narro^^^less of the hole 

 through which they have had to pass. It even happens that they stick fast in the hole, 

 and perish there. They are extremely small, their breadth not exceeding the 1896th 



ance for some days past. Instead of its usual brightness, the surface has been to a considerable extent 

 covered with what appears to the naked eye a sort of nasty froth or scum, emitting a foetid smell. In the 

 mornings, when it has been usually calm, this scum has presented itself in broad belts and fields, and by 

 the afternoon, after being exposed' to the sea-breeze, it is broken down into streaks, lying in the direction 

 of the wind, which, if it blows pretty fresh, disperses it altogether. We have examined some of this 

 unusual substance in a tumbler of salt water, and were not a little surprised to find, that while it Hoated 

 on the surface, in the form of a scum, some parts of a yellowish-green, and some of a purplish-brown 

 colour, it tinged the whole water of a beautiful violet. We afterwards found that the whole water in 

 the bucket, in which it was brought from the sea, had acquirod the same colour; and, indeed, it 

 appeared to us the other day, when it was very abundant, as if the sea itself had been stained of this 

 beautiful tint. We found, on minute inspection, that it consisted of an infinite multitude of small 

 s^ndle-shaped bodies, each of which, in its turn, was a bundle of small threads jointed but unbranched, 

 and seemingly very brittle. We have no doubt but it is a vegetable production in the sea, something 

 similar to the green substance which covers stagnant pools of fresh water. The most remarkable an 1 

 unpleasant feature is its foetid odour. AMien we read in books of voyages, of ships sailing for so many 

 hours through seas of a blood-colour, and similar wonders, we are apt to suppose the author is taking the 

 liberty of a traveller ; but witnessing such a phenomenon as this, is calculated to prepare us for giving 

 them more credit." 



Fig. VII. Achlya prolifera. — l.The club-shaped spore-chamber; 2. the same emptied of its spores ; 

 3, 4. as pore-chamber much less magnified, containing two terminating spores, and a dead one ; 5. a 

 piece of the thread at an earljf period, with the lines of motion. 



C 



