(n.) A fossil cephalopod shell related to the nautilus. There are many genera and species, and all are extinct, the typical forms having existed only in the Mesozoic age, when they were exceedingly numerous. They differ from the nautili in having the margins of the septa very much lobed or plaited, and the siphuncle dorsal. Also called serpent stone, snake stone, and cornu Ammonis.
Example Sentences:
(1) Start your exploring at Bearreraig Bay, where, if you are lucky, you may find belemnites, ammonites and bivalves.
(2) An ambitious project to showcase the prehistory of the south coast of England, famous for its marine fossils from ammonites to giant sea reptiles, has attracted support from David Attenborough and Eden Project founder Tim Smit.
(3) Everest is published by Ammonite Press on 22 May, priced £40.
(4) Cretaceous-Tertiary, 65 million years ago An giant asteroid impact on Mexico, just after large volcanic eruptions in what is now India, saw the end of the dinosaurs and ammonites.
Cephalopod
Definition:
(n.) Alt. of Cephalopode
Example Sentences:
(1) Lens crystallins were isolated from cephalopods, octopus and squid.
(2) The photopigments, rhodopsin and retinochrome, have been localized in cephalopod retinae using light and electron microscopic immunocytochemical methods.
(3) Occasionally, anti-RALBP antibodies were seen to react weakly with "IRBP" in some cephalopods.
(4) In the cephalopod lens, however, the sum inside was much lower than that outside.2.
(5) We report here that a transparent tissue, derived from muscle but functioning as a lens in the light-emitting organ of a squid, Euprymna scolopes, shows striking biochemical convergence with the epidermally derived ocular lenses of some mammals and cephalopods.
(6) Sequence similarity between this major cephalopod crystallin and glutathione S-transferase were found, which suggested some enzymatic role of crystallins inside the cephalopod lens.
(7) This polyclonal antiserum also cross-reacted with the ALDH-like crystallins found in the ocular lenses of certain mammals and cephalopods.
(8) Screening of lens homogenates for the identification of lactate dehydrogenases was undertaken for the representative species from five major classes of vertebrates plus the cephalopod of invertebrates.
(9) The potential of the [14C]deoxyglucose technique as a powerful tool in studying the functional organization of cephalopod brains is discussed.
(10) Catecholamines and 5-hydroxytryptamine were measured fluorimetrically in nervous tissue of cephalopod molluscs.2.
(11) Fourth, nociception can explain the behavior of insects and perhaps other invertebrates (except possibly the cephalopods).
(12) The photosensitive vesicles of cephalopods are extraocular receptors present either in the mantle or on the head.
(13) A single layer of cell secrets the hard cephalopod beaks.
(14) The total amount of retinochrome in the retina was several times higher than that of rhodopsin, distinguishing the gastropod eye from the cephalopod eye.
(15) The requirement of live marine prey for cephalopod mariculture has restricted its practicality for inland research laboratories, commercial enterprises and home aquarists.
(16) When it comes to the battle of the molluscs, cephalopods win tentacles down.
(17) To clarify the formation process of acid metarhodopsin in the cephalopod rhodopsin cycle, changes in the difference spectrum of squid (Todarodes pacificus) rhodopsin in acid (pH 5.7, or pH 6.1) and alkaline (pH 10.2) solutions were studied at various temperatures by applying the flash photolytic technique.
(18) Crude patterning may take place in the basal and, perhaps, peduncle lobes in cephalopods and in the lower and intermediate medulla in teleosts.
(19) Progesterone and testosterone were obtained from the gonads and liver of cephalopods and from the whole body of crustaceans.
(20) In this respect this retinal-binding protein could have a role very similar to that postulated for the well-known cephalopod retinochrome, that serves to catalyze the formation in the presence of light of 11-cis retinal in photo-receptor cells and to provide it for the reconstitution of rhodopsin during the visual cycle.