My brother snapped these beautiful Mares' Tails, as we always used to call them. Their scientific name is Cirrus uncinus, which apparently means 'curly hooks'.
Mares' tails are high altitude (20,000 feet and up) ice crystals clouds. The hooks bit is because sometimes the ends bend like hooks, and those in the photo don't quite have the classical shape.
It's interesting that different kinds of cloud have binomial names with a genus and a species, a form generally reserved for living things. But with the help of Gemini I found that viruses have binomial names, although whether viruses are alive is debatable.
Linnaeus even explored a similar naming scheme for minerals, considered by him a third 'kingdom' (and we still speak of 'Animal, Vegetable and Mineral') but ultimately it was not adopted by the scientific world.
Clouds are an exception: Luke Howard who at the beginning of the 19th century famously pioneered assigning systematic names to cloud forms imitated Linnaeus in using binomial names and his basic scheme has survived.