INVERTEBRATE ANIMALS. 57 



sand or mud, with which, when opened, their intestines 

 are found to be filled ; these substances seem to have 

 been swallowed for the sake of the animal matter mixed 

 up with them. Estimated number of species : recent, 

 33; British, 4; fossil, 176. From the Chalk upwards. 



^ Examples of Meoma, Desoria, Xantliobrissiis, 

 Tripylus, Plagionotus, Schizaster, Kleinia. 



Group 154.— Sub-Class HOLOTHUROIDA. bxo^oupiov, 

 Greek name for the animal. Many links are missing 

 between the Sea-urchins and the Sea-cucumbers, Holo- 

 thuridce. The latter are worm-like animals, possessing 

 a tough flexible skin, and bearing around the mouth a 

 five-rayed coronal of feathery tentacles. The order 

 includes two families : I. SynaptidcB, simple in form, 

 and moving by means of anchor-shaped spicules 

 attached to papillae or minute warts. II. Holothuridce , 

 several species of which are known in commerce as 

 Beche-de-mer or Trepang, used in China as turtle is 

 used in this country. Estimated number of species: 

 recent, 97 ; British, 15. 



IT Examples of Trepang as prepared by Malays for 

 the Chinese market. Coloured drawings of 

 some of the species, and of their internal 

 anatomy. Specimens preserved in liquid. 



