Hyolitha are enigmatic animals with small conicalshells. They are known only from the Cambrian era. The conical shells have a cover (operculum) and two curved supports known as helens. The shells are calcerous and are usually triangular or elliptical in cross section. Some species have rings or striations. Most are one to four centimeters in length. Some authors treat them as molluscs, but it is generally agreed that there is no very strong argument to do so. Phyla Porifera (sponges) Ctenophora (comb jellies) Cnidaria Placozoa Bilateria Acoelomorpha Orthonectida Rhombozoa Myxozoa Superphylum Deuterostomia Chordata (vertebrates, etc. ... In geometry, a (general) conical surface is the unbounded surface formed by the union of all the straight lines that pass through a fixed point — the apex or vertex — and any point of some fixed space curve — the directrix — that does not contain the apex. ... The hard, rigid outer calcium carbonate covering of certain animals is called a shell. ... The Cambrian is a major division of the geologic timescale that begins about 542 million years before the present (BP) at the end of the Proterozoic eon_geology and ended about 490 million years BP with the beginning of the Ordovician period. ... In Biology operculum (Latin for little lid) has been used to describe several completely separate features. ... In bodybuilding, striations are the tiny grooves of muscle across major muscle groups characteristic of a well-developed body. ... Classes Caudofoveata Aplacophora Polyplacophora - Chitons Monoplacophora Bivalvia - Bivalves Scaphopoda - Tusk shells Gastropoda - Snails and Slugs Cephalopoda - Squids, Octopuses, etc. ...
Despite the fact that Hyolithid shells are quite common as fossils, next to nothing is known about their ancestry and internal structures. They were obviously benthic (bottom-dwellers), and there is some evidence that they were carnivores. FOSSIL is a standard for allowing serial communication for telecommunications programs under DOS. FOSSIL stands for Fido Opus Seadog Standard Interface Layer and was made by a group of Fidonet sysops to make their software work on different machines. ... Carnivores are animals that eat a diet consisting mostly of meat. ...
Find in a Library: A bibliographic index of North American late Paleozoic Hyolitha, Amphineura, Scaphopoda, and Gastropoda; an objective paleontologic compliation through 1966 extended from and including references in a similar index by Stuart Weller, 1898.
A bibliographic index of North American late Paleozoic Hyolitha, Amphineura, Scaphopoda, and Gastropoda; an objective paleontologic compliation through 1966 extended from and including references in a similar index by Stuart Weller, 1898.
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