Brachiopods are far more numerous than the Mollusca properly so-called.
Besides brachiopods and oysters, these beds have furnished a species of Perna (P.
Pecten, besides Brachiopods (Terebratula digona, which looks very like a sack of flour, and T.
In the modern world about one hundred species of Brachiopods are known, belonging to about twenty genera, some of which differ considerably from the LingulA|.
Supposing these to be all, it is remarkable that we have no Protozoa or Corals or Echinoderms, and that the types of Brachiopods and Crustaceans are of comparatively modern affinities.
The seashells, bothbrachiopods and mollusks, are in some respects the most important to the geologist of all fossils.
Colonies of brachiopods and other lime-secreting animals occupied the sea bottom, and their debris mantled it with sheets of limy ooze.
Brachiopods have dwindled greatly in the number of their species, while mollusks have correspondingly increased.
Brachiopods occupied an important place; most typical were the Productids, some of which reached a great size and had very thick shells.
Notwithstanding the antiquity of this Russian formation, it should be stated that both of these genera of brachiopods have been also found in the Upper Silurian of England, i.
Not one of these is common to rocks newer than the Palaeozoic, and the brachiopods are the only group which have furnished species common to the more ancient or Carboniferous rocks.
The more highly organized articulate brachiopods have valves of carbonate of lime more securely joined by a hinge with teeth and sockets (Fig.
In Brachiopods it is turned dorsalwards, and in phylactolaematous Polyzoa ventralwards.
Setae of this kind are found in chaetopod-like larvae of some Brachiopods (Argiope, fig.
At the western foot of the Ida massif calcareous beds with corals, brachiopods (Rhynchonella inconstans, &c.
Polyzoa were abundant; brachiopods were fairly common, though subordinate to the pelecypods; they were mostly rhynchonellids and terebratulids, which lived side by side with the ancient forms, like Crania and Discina.
The brachiopods and trilobites have likewise been made use of for zonal purposes among the oldest sedimentary formations.
Contains Reports on Antiquity of Caverns and Cavern Life of Ohio Valley, and Fossil Brachiopods of Ohio Valley by Shaler; The American Bisons, Living and Extinct; by Allen; Prehistoric Remains of Kentucky by Lucien Carr and Shaler.
Preliminary Catalogue of the Shell-Bearing Marine Mollusks and Brachiopods of the southeastern coast of U.
The Mollusca are chieflyBrachiopods of great size.
It may, however, be pointed out that Brachiopods seem to belong to that class of animal which commences life as a larva with three segments, and that tri-segmented larvae have been found now in several of the larger groups.
The histology of Brachiopods presents some peculiar and many primitive features.
The suggestion to place Brachiopods with the Polyzoa, Phoronis, Rhabdopleura and Cephalodiscus, in the Phylum Podaxonia made in Ency.
Apart from the asymmetry of the intestine caused by the lateral position of the anus in the two genera just named, Brachiopods are bilaterally symmetrical animals.
The nervous system of Brachiopods has, as a rule, maintained its primitive connexion with the external epithelium.
In spite of some assertions to the contrary, all the Brachiopods which have been carefully investigated have been found to be male or female.
By the aid of these cilia the larva swims actively, but owing to its minute size it covers very little distance, and this probably accounts for the fact that where brachiopods occur there are, as a rule, a good many in one spot.
Moreover, the brachiopods of the palaeozoic age he would regard as larger than those existing now which have sunk by 'degradation' into inferior importance.
The prevalence of thebrachiopods in the Silurian period over the cephalaspidae proves little.
The race of the brachiopods goes back to the beginning of the geologic record.
The mouth in the brachiopods is flanked by two curiously coiled and feathered arms which lie within the cavity between the shells, and are supported by skeletal rods attached to the upper shell.
Amongst other well-known Devonian Brachiopods may be mentioned the two long-lived and persistent types Atrypa reticularis (fig.
The Brachiopods continued to flourish during the Upper Silurian Period in immense numbers and under a greatly increased variety of forms.
Amongst the remaining Upper Silurian Brachiopods are the extraordinary Trimerellids; the old and at the same time modern Linguloe, Discinoe, and Cranioe; together with many species of Atrypa (fig.
The Brachiopods exhibit the Palæozoic Athyris, Retzia, and Cyrtina, with the Triassic Koninckia and the modern Thecidium.
Barrande, in the publication before us, discusses the brachiopods with reference, first, to the variations observed within the limits of the species, eliminating in this way mere synonyms and varieties mistaken for species.
The total number of species of brachiopods in these formations is six hundred and forty, giving an average of 45.
Defn: A division of brachiopods including those which have a calcareous shell furnished with a hinge and hinge teeth.
Defn: A genus of brachiopods of which some species are still living, while many are found fossil.
The peduncle or stem by which various marine animals are attached, as certainbrachiopods and goose barnacles.
Defn: A genus of brachiopods which includes many living and some fossil species.
Defn: A genus of brachiopods of which many species are found in the fossil state.
Illustration] Among the Mollusks, Brachiopodsare still prominent, one new genus among them, the Productus, being very remarkable on account of the manner in which one valve rises above the other.
They differ from the Brachiopods chiefly in the higher character of their breathing-apparatus; for they have free gills, instead of the net-work of vessels on the lining skin which serves as the organ of respiration in the Brachiopods.
Among theBrachiopods the higher sloping-shoulder type displaces the square-shoulder shells.
The Brachiopods have passed into entirely new and more advanced species in the many advances and retreats of the shores, but the Molluscs show more interesting progress.
The Brachiopodsand Molluscs still abound, but the Molluscs begin to outnumber the lower type of shell-fish.
Molluscs and Brachiopods and small fishes fill the list, but are of little instructiveness for us, except that they show a general advance of species.
Pteropods constituted another class in his division of the type of Mollusks; but these animals, again, form only an order in the class of Gasteropoda, as Brachiopods form an order in the class of Acephala.
With the latter group the Brachiopodswere formerly united by Huxley, under the name of Molluscoidea.
The shells of Brachiopods are equal-sided; that is to say, the right and left valves match; but they are inequivalve, the ventral valve being much the biggest.
There is no reason, for example, why corals should not have been preserved as well as Trilobites, or why Brachiopods should have been preserved rather then ordinary bivalves.
The above list will hopefully give you a few useful examples demonstrating the appropriate usage of "brachiopods" in a variety of sentences. We hope that you will now be able to make sentences using this word.
