Arachnida A·rach·ni·da (ə-rāk'nĭ-də)
A class of arthropods that includes spiders, scorpions, mites, and ticks.
Contributions to the knowledge of the life history of arachnida.
On the contrary, this particular point is one in which they agree with the higher arachnida.
In arachnida, Myriapoda, and probably also Insecta, the body cavity is primitively prolonged into the limbs.
All arachnida, including Limulus, feed by suctorial action in essentially the same way as Scorpio.
Even towards the nearer provinces of the Myriopoda and arachnida I can find no bridge.
Formerly it was regarded as a crustacean; now it is classed by some authors with the arachnida, along with scorpions and spiders.
In defining the arachnida I shall only mention those particulars in which they differ from Insect in their external anatomy.
These have small and insignificant rami, or none at all, a feature in which the arachnida differ from them.
These, though somewhat connected with the rotifers, are considered to belong to a low division of the arachnida (spiders, &c.).
The next type of form with regard to the oral organs is that of the arachnida.