Essay On Horseshoe Crabs

Horseshoe crabs are marine living fossils, probably traced back to 485 million years ago. There are two horseshoe crab species found in Hong Kong.

Horseshoe crabs are an ancient marine chelicerates, identified as the Class Merostomata, Order Xiphosura. The animals are identified by the possession of appendages around their ventral mouth and their swimming legs at their distal end. They have closer lineages with trilobites and arachnids such as spiders and scorpions instead of the "real" crabs which are crustaceans. Four extant species of horseshoe crabs are found and have survived over the geological period. They are classified to three genera in two families under the Superfamily Limulacea. They have hardly changed in millions of years. The oldest horseshoe crab fossils are probably traced back to the Cambrian period, which is nearly 485 million years ago. Therefore, the existing

Long-tailed Skink

They can reach a full length of about 10-12 inches, which around three over four parts of that length will consist of the tail.About the Tail, long tailed lizards have a prehensile tail, meaning they can wrap it around things to help hanging on.

They are usually dark greenish brown to brown on the back with a light or sometimes creamy white belly. A brown stripe with a thin white or black border often runs down each side of the long tailed lizard, though the coloration and stripe patterns can vary.

The Takydromus sexlineatus is found throughout South East Asia, and is inhabited to countries including India, China, Thailand, and Indonesia. If a potential predator approaches, they will first remain still and not quite completely, and then if the danger still get closer, they will flee to the safety of foliage. Both sexes use arm-waving movement, which similar to a front crawl swimming action, apparently to communicate with each other. They are very agile and fast.