Their chief colonies in this sea were Astacus and Heraclea in Bithynia, and another Heraclea in the Crimea.
The chief cleruchies of Pericles are: Thracian Chersonese (453-452), Lemnos and Imbros, Andros, Naxos and Eretria (before 447); ' Brea in Thrace (446); Oreus (445); Amisus and Astacus in the Black Sea (after 440); Aegina (431).
], an ancient town at the head of theGulf of Astacus, which opens on the Propontis, was built in 264 B.C. by Nicomedes I.
The west coast is indented by two deep inlets, (t) the northernmost, the Gulf of Ismid (anc. Gulf of Astacus), penetrating between 40 and 50 m.
It has been discovered that at the beginning of the Eocene the lake of Rilly occupied a vast area east of the present site of Paris; a water-course fell there in cascades, and Munier-Chalinas has reconstructed all the details of that singular locality; plants which loved moist places, such as Marchantia, Asplenium, the covered banks overshadowed by lindens, laurels, magnolias and palms; there also were found the vine and the ivy; mosses (Fontinalis) and Chara sheltered the crayfish (Astacus); insects and even flowers have left their delicate impressions in the travertine which formed the borders of this lake.
The relative proportions of these three divisions vary considerably, and the extreme abbreviation of the mid-gut found in the common crayfish (Astacus) is by no means typical of the class.