Phyllopa.
Distinguished by the number of feet, and by the lamella or folia ceous form of the joints, ilpresenting, according to Latreille, the Al yriapods in the class Insccta. The eyes are always two in number, formed of a sort of network, and sometimes placed on pedieles; many have besides a single smooth eye.
Ceratophthalma, Latreille, have ten pairs of feet at the least, and the maximum of those organs in this group is said to be 22. There is no vesicular body at their base, and the anterior feet are never so long as the others, nor are they ramified. The body is either inclosed in a shell-ease, like a bivalve shell, or naked, the thoracic divisions being each furnished with a pair of feet. The eyes are sometimes sessile, small, and placed very nearly together; sometimes, and indeed most frequently, they are mounted on the extremity of two moveable pedielea. The eggs are either internal or external, and inclosed in a. capsule.
Eyes sessile, immoveable ; body inclosed in an oval case like a bivalve shell ; ovaries always internal.
The sub-genus Limnadia of Adolphe Brongniart is an example or this structure. Limnadia Ilermanni (Adel. Brongn.), Daphnia gigas of Hermann, occurs in great numbers iu the little pools of the forest of Fontainebleau, and we must refer the reader to Brouguiart's Memoir in the 6th vol. of the 'Memoires du Mus6um d'Histoire Naturello ' for its description.' Each eye situated at the extremity of a pedicle ou both sides of the head ; body naked and annulated throughout its length; no enveloping case or shell ; eggs contained in an elongated capsule situated towards the base of the tail, or at the posterior extremity of the body and thorax in those which have no tail.
1. With a Tail.
To this subdivision belongs the Brine-Shrimp or Brine-Worm, Anemia or A Hem id of Leach, Branchipus of Latreille, and of Benedict Prevost and Jurine. We are uow arrived at that develop ment of form in the Branchiopods where the numerous legs or feet become paddles adapted simultaneously to the purposes of locomotion and respiration.
The Brine-Worm or Brine-Shrimp, Artesia sal ina of Leach, Cancer salinus of Linnxus, Gammarus salmis of Fabrieius, Artemis salinus of Leach, Artomisus salinus of Lamarck, when full-grown, is about half an inch in length and very transparent : it is said to have been first discovered in the salt-pans at Lymington by Dr. Maty. There these animals are found in myriads, in rapid and continual motion in the salteme, which are the open tanks or reservoirs where the brine is deposited previous to boiling. The brine attains the desired strength by evaporation from exposure to the sun and air in about a fortnight. A pint contains about a quarter of a pound of salt, and in this concentrated solution, which, as Mr. Hackett observes, instantly destroys most other marine animals, the Brine-Shrimp revels. It is I further said that these Brine•Worms are never found in the sun-pans where the brine is made by the admission of sea-water during the summer, and which are emptied every fortnight, but only hi the pits or reservoirs (clearers) where it is deposited after it is taken out of the pans, and where some of the liquor constantly remains. So persuaded are the workmen of their utility in clearing the liquor, that they aro accustomed to transport a few of the worms from another saltern if they do not appear at their own, and they increase greatly in a few days. Little however was known of the natural history of this animal till Mr. Thompson published his interesting observations In the 6th number of his 'Zoological Researches' (1834). He has In the Hastings Sands. Desmarest notes the species as found in great abundance near the mountain of Gergovie, in the department of the Puyde•Dama, and at the Balme-d'Alher, between Viehy-les-13ains and CUMSC. Their great fruitfulness and the frequent moults noticed Shell yellowish-green, banded with green. A, aide view; B, view looking upon the binge. The bands commence behind the eye.