In the middle ages Ostia regained something of its importance, owing to the silting up of the right arm of the Tiber.
Peripatus is an Arthropod, as shown by (1) the presence of appendages modified as jaws; (2) the presence of paired lateral ostia perforating the wall of heart and putting its cavity in communication with the pericardium; (3) the presence of a vascular body cavity and pericardium (haemocoelic body cavity); (4) absence of a Derivisceral section of the coelom.
In 1800 Henry was able to return to Rome, and in 1803, being now senior cardinal bishop, he became ipso facto dean of the Sacred College and bishop of Ostia and Velletri.
Nero's scheme for the construction of a canal from Lake Avernus to Ostia would have restored the balance in its favour (though it certainly could not have been continuous all the way to Rome with the means of engineering then available).
The papal states were in a turmoil, and the powerful Colonna faction seized Ostia in the name of France.
Its commerce increased with the growth of Rome, and this, and the decay of agriculture in Italy, which obliged the capital to rely almost entirely on imported corn (the importation of which was, from 267 B.C. onwards, under the charge of a special quaestor stationed at Ostia), rendered the possession of Ostia the key to the situation on more than one occasion (87 B.C., A.D.
Of the church in Ostia there is no authentic record before the 4th century A.D., though there are several Christian inscriptions of an earlier date; but the first bishop of Ostia of whom we have any certain knowledge dates from A.D.
In 1279 Pope Nicholas sent his nephew, the friar preacher Latino Frangipani Malabranca, whom he had created cardinal bishop of Ostia the same year, to reconcile the parties in Florence once more.
Excavations on the site of Ostia were only begun towards the close of the 18th century, and no systematic work was done until 1854, when under Pius IX.
The heart was tubular in form, 3a and 3b, Two crustacean teeth extending the whole length of the (of Dithyrocaris) from the body, and having a pair of ostia Carboniferous series of in each somite.