As an illustration of this metamorphosis, we give figures of theZoea Taurus in two states, viz.
The Zoea of the Tatuira (Figure 25) also appears to differ but little from those of the true Crabs, which it likewise resembles in its mode of locomotion.
Consequently these processes of the carapace may be regarded as acquired by the Zoea itself in the struggle for existence.
Nevertheless the supposition that the Insecta had for their common ancestor a Zoea which raised itself into a life on land, may be recommended for further examination.
Older larva produced from the Zoea represented in Figure 32.
The tail soon acquires the furcate form with which we made acquaintance in the last Prawn-Zoea described.
Zoea of this species particularly from other Zoeae (the employment of the anterior limbs for swimming, the furcate tail, the simple heart, the deficiency of the paired eyes and abdomen at first, etc.
So far as the zoea was concerned, this assumption was soon shown to be erroneous, and the secondary nature of this type of larva is now generally admitted.
Whether that common primary form of all Tracheata, which in my General Morphology I have named Protracheata, did develop directly out of genuine Ringed worms, or at first out of Crustacea of the Zoea form (Zoepoda, p.
The zoea and megalopa stages of Crabs, the zoea and schizopod stages of Prawns and Shrimps, are often conspicuous by their numbers, or we may find swarms of the nauplius and cypris larvae of Barnacles.
As a matter of fact, the zoea just described is not quite the earliest stage of the Shore Crab, for when hatched from the egg it is without the spines on the carapace, and is slightly different in other respects.
On the other hand, it is impossible to believe that any of the ancestors of the Shore Crab resembled, even remotely, the zoea stage with which the life-history of the individual now begins.
In the later stages of the zoea the rudiments of the hinder thoracic limbs and of the swimmerets appear as little buds.
Willey has been able to prove definitely that the female visits the sea for the purpose of hatching off the eggs, and that the young are hatched in the zoea stage.
In Penaeus the larvae are of comparatively simple form, but in the allied genus Sergestes the zoea has a very remarkable appearance.
The Anomura are also hatched as zoeae, and one of the most remarkable forms common in tow-nettings in British waters is the zoea of the little Porcelain Crabs (Porcellana--Fig.
The development of Zoea into the perfect animal has been well described by Mr. Spence Bate[27] in the case of the common crab (Carcinus maenas).
The Zoea form of larva differs from the perfect prawn or crab in the absence of the middle portion of the body and its appendages.
The Zoea is a minute transparent organism, swimming at the surface of the sea.
After a time the zoea throws off its skin and appears in quite a different form.
And as the zoea is a kind of crustacean caterpillar, so the megalopa is a kind of crustacean chrysalis.
The maggot is the larva of the fly, and the zoea is the larva of the Crab.
Again and again its skin splits, and a rather differentzoea appears.
With crowds of its brothers and sisters, thezoea kicks about on the surface of the sea.
After the larva has moulted several times it appears as in the illustration on page 248--the last zoea stage.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "zoea" in a variety of sentences. We hope that you will now be able to make sentences using this word.
