The formation of zoospores may be easily observed in the brown sea weed _Ectocarpus Siliculosus_ we have already mentioned. This plant, as we have already remarked, consists of thin, thread-like rows of single cells and from time to time it is branched. At certain periods of the year, moderately large, pear shaped swellings occur on the threads of the sea-weed. If we are either fortunate or exceptionally patient we may chance to be examining one of these swellings under the microscope at the moment when it bursts and sets free its contents. Should we have this good fortune we must hasten to magnify more highly the zoospores which have escaped from the pear shaped spore case. Here we may add the caution that we shall only witness the bursting of the spore case if we examine our specimen in sea water; we should require more than the patience of Job to watch for its bursting in the dry state, for it will never come to pass. A careful study of a zoospore will show that it swims in a peculiar manner. One of the little whips is directed forwards, the other trails behind. After a short period of activity the zoospore comes to rest, loses all means of propulsion, germinates and grows into a new _Ectocarpus_ plant. Sometimes this _Algæ_ reaches a low ebb of vitality, it requires a new lease of life as it were, when this state is reached another form of increase takes place. The events in this case may also be witnessed under the microscope. From very similar spore cases a number of zoospores are liberated and for a time they swim about freely. If now we watch carefully we shall notice that one of the active little bodies comes to rest and that the others lose no time in swarming round it. One of these swarming zoospores fuses with the individual which first ceased swimming about, with the result that a much larger, non-swimming individual is formed which, after a short resting period, germinates and grows into a new sea weed. The remainder of the zoospores will come to rest later and germinate to form new plants just as though no fusion had taken place with two of their number. Here we see the beginnings of male and female increase amongst sea weeds; the individual which first comes to rest is looked upon as the female and the one with which it fuses as the male. [Illustration: _By the courtesy of Messrs. F. Davidson & Co._ THE FEELER OF A COCKCHAFER The end of the feeler consists of a number of plates, which can be spread fanwise. The pores visible on the plates are the insect’s organs of smell. ]