88 
LIFE, IN ITS LOWER FORMS. 
at the good pleasure of the creature projected, and un- 
folded to a length ten or twelve times that of the body. 
Each thread is set with a single row of short filaments, at 
regular distances, which are ordinarily carried in spiral 
curves, capable of elongation or contraction like the 
cables themselves. 
The crystalline Cydippo represents the CiUograde order 
of Acalephm, or that whose motion is performed by means 
of ciliary paddles. Another order is the Physograde, where 
the apparatus for swimming consists of one or many blad- 
ders inflated with air, probably generated by the animal. 
An example of this tribe is well-known to those who 
navigate the warmer regions of the ocean as the Portu- 
guese man-of-war ( Phjsalia pelagica ), -where we have seen 
it in myriads studding the calm surface of the glittering 
deep. Nor is it wholly a stranger to more northern climes, 
for fleets of these adventurous craft are sometimes driven 
by the force of Atlantic currents far out of their reckon- 
ing, and stranded upon our western shores. 
This singular animal consists of an oblong bladder of 
clear membrane, surmounted by a thin crest, which runs 
along its upper edge, and is capable of being contracted, 
so as to be almost invisible, or of being elevated into a 
tense and lofty sail. When in the latter condition, the 
whole forms a beautiful object; the glossy, colourless 
bladder reflecting the sun’s rays, while the upper half of 
the sail is tinged with a delicate rose-colour, and the bot- 
tom of the bladder with a rich azure. As the little thing 
tosses and floats upon the waves it bears a striking resem- 
blance to a child’s toy-ship ; and even those most familiar 
with its appearance gaze upon it with ploasure. We 
