Sugar glider (Petaurus breviceps), has a potagium or thin membrane from wrist to ankle allowing it to glide for short distances, Queensland, Australia, Pacific

Small giant clam (Tridacna maxima), Namu atoll, Marshall Islands, Pacific

Giant fluted clam (Tridacna squamosa), Namu atoll, Marshall Islands, Pacific

Fluted giant clam (Tridacna squamosa) mantle detail, Namu Atoll, Marshall Islands, Micronesia, Pacific

Giant fluted clam (Tridacna squamosa) on sandy bottom, Namu atoll, Marshall Islands, Pacific

Fluted giant clam (Tridacna squamosa), Rongelap, Marshall Islands, Micronesia, Pacific

Small giant clam (Tridacna maxima) surrounded by lobe coral (Porites lutea), Namu atoll, Marshall Islands, Pacific

Fluted giant clam (Tridacna squamosa), Rongelap, Marshall Islands, Micronesia, Pacific

Builders lay under floor insulation into a house extension in Ambleside, Cumbria, England, United Kingdom, Europe

Small giant clam (Tridacna maxima) surrounded by lobe coral (Porites lutea), Namu atoll, Marshall Islands, Pacific

Reef octopus (Octopus cyanea) eye and siphon detail, Rongelap, Marshall Islands, Micronesia, Pacific

Reef octopus, Octopus cyanea, eye and siphon detail, Rongelap, Marshall Islands, Micronesia

Horseshoe clam, Hippopus hippopus, Rongelap, Marshall Islands, Micronesia

Giant clam, Tridacna gigas, siphon detail, Rongelap, Marshall Islands, Micronesia

SARS-CoV-2, COVID-19 Virus, TEM

Meninges, Drawing

The diffusion of potassium cations across a semipermeable membrane.

Aids Virus Infection, Drawing

The diffusion of water across a semipermeable membrane.