Nigel Cattlin / Doyenne du Comice pear (Pyrus communis) fruit with deformity and internal hard growth caused by Pear stony pit virus, cross section. Berkshire, England, UK. October.

Alex Mustard / Veined octopus (Amphioctopus marginatus) between clam shell halves. Ambon, Maluku Archipelago, Indonesia. Banda Sea, tropical west Pacific Ocean.

Inaki Relanzon / Half head portrait of Arabian oryx (Oryx leucoryx) in Dubai, UAE

Alex Mustard / Veined octopus (Amphioctopus marginatus) resting on top of the two halves of an old clam shell on the sandy seabed. These octopus regularly carry pieces of shell so they can use them as protective arm...

Alex Mustard / Veined / Coconut octopus (Amphioctopus marginatus) makes a home between a piece of plastic and a shell, holding the two halves together with its sucker covered legs. Anilao, Batangas, Luzon, Philippin...

Juan Carlos Munoz / Two halves of Guinness in restaurant, Dingle Village, Dingle Peninsula, County Kerry, Republic of Ireland. September 2015.

Adrian Davies / Inkstain Bolete (Boletus pulverulentus) cross section showing characteristic staining, Surrey, England, UK, August.

Alex Mustard / Veined octopus (Amphioctopus marginatus) using two halves of a coconut as a home. Lembeh Strait, North Sulawesi, Indonesia. Molucca Sea.

Alex Mustard / Veined octopus (Amphioctopus marginatus) using two halves of a coconut as a home. Lembeh Strait, North Sulawesi, Indonesia. Molucca Sea.

Wild Wonders of Europe / Möllers / Two halves of freshly skinned and prepared female Wild boar (Sus scrofa) that was shot during a driving hunt in the forest area outside the village of Mehadia, Caras Severin, Romania, October 2012

Alex Mustard / A young veined octopus (coconut octopus: Amphioctopus marginatus) shelters in an empty bivalve shell by pulling the two halves together with its arms. Lembeh Strait, Molucca Sea, Sulawesi, Indonesia.

Philippe Clement / Dog cockle (Glycymeris glycymeris) shell split in to the two halves showing the inside and the outside, Normandy, France

Philippe Clement / Common mussel (Mytilus edulis) shell, both halves separated, Belgium

Jane Burton / Buff Pekin {Gallus gallus domesticus} hatch sequence 3/9. The chick begins to push the two halves of the shell apart

Tony Wu / Male Broadclub cuttlefish (Sepia latimanus) approaching female to attempt mating, with split body pattern and coloration into two distinct halves. East China Sea, Kagoshima Prefecture, Japan.

Enrique Lopez-Tapia / Egg-shaped granitic boulder split in two, weathering caused by extreme desert temperatures. Karlu Karlu / Devils Marbles Conservation Reserve, Northern Territory, Australia.

Enrique Lopez-Tapia / Granitic boulder split in two, weathering caused by extreme desert temperatures. Karlu Karlu / Devils Marbles Conservation Reserve, Northern Territory, Australia.