Marvels of the Universe 1047 
From this brief outline, it will be seen that the Sea Squirts form a vast and varied group; they 
range from arctic to tropical seas, and from sea-surface to almost abyssal depths. The brightly 
coloured ones present a perplexing problem to the student of colours and coloration in relation 
to environment. 
In all higher forms, colours and their arrangement play a definite and important part, either 
as protective and mimetic coloration, when they tend to render the individual inconspicuous in 
its surroundings; warning colours, when the individual is either armed or is not good to eat; 
sexual coloration and recognition markings, when colours or their arrangement have some relation 
to sex during the courting season, and so forth. But in these Ascidians, none of these conditions 
seem to be implied—bright reds and bright greens vie in splendour side by side, as conspicuous 
as can be, and yet they are good to eat, and masses of those that affix themselves to weeds are 
frequent in stomachs of dog-fishes and other predacious things of the sea. Thus protective 
coloration and warning coloration do not apply. The Ascidians do not court, therefore sexual 
selection or recognition markings do not come in. Nor are their colours due to the food they 
eat, for the reds, the greens, the purples and the yellows all feed on the same material, 
viz., whatever comes to their net. This problem therefore offers an interesting field for 
investigation, for up to now, the reason for these striking features we do not know. 
OMEN PD SAN Das 
MAKER 
BY HAROLD BASTIN. 
THE Oak-apple, or “ King Charles’ 
apple,” as it is often called in com- 
memoration of an oft-told incident in 
this monarch’s life, is among the most 
familiar of all those natural objects 
which reappear with unfailing regularity 
aS one season succeeds another. Yet 
comparatively few people know the true 
history of an Oak-apple, or how it is 
produced. The writer has heard it 
described as a kind of fruit ; and again 
as a species of fungus; while some of 
the old naturalists invented far more 
fantastic theories to account for its 
origin. Even when it became known 
that an Oak-apple contains numerous 
white grubs which in course of time 
flies,’ the 
a 
give rise to a brood of 
mystery was not lessened, for nobody 
seems to have thought that the insects 
could be in any way responsible for the 
substance upon which they feed.  In- 
deed, the grubs were supposed to occur 
PYROSOMA. 
spontaneously Mm the Oak-apple—exactly A single iidividual detached from the colony on page 1045. The 
as maggots were at one time believed letters a to d have the same significance as in the previous diagram; @ is 
the mouth, f the stomach, / intestine, A ovary, f oviduct, atrial cavity, 
to be mysteriously generated in meat as _—& Juminous organs. 
