Fossil sponge,Peronidella furcata. Sponges,or Porifera,are marine animals who often live grouped together in colonies. They possess no nervous system,no internal organs,no mouth and no anus. They have a calcareous or siliceous skeleton made up of spicules that fuse together to form a rigid frame. Their are numerous inlets on the exterior walls of this frame through which food is drawn,by means of flagellae,into the gastric cavity. This example,from the Lower Greensand of the Cretaceous age (around 136 million years ago),was discovered in Faringdon,Berkshire in the U.K | |
Licence : | Droits gérés |
Crédit: | Science Photo Library / Land, Martin |
Taille de l’image : | 3438 px × 2421 px |
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