14 GUIDE TO THE CORAL GALLERY. 



High Wall Eiicecryphalus schultzei has only two segments, the lower being 



Case expanded out, and the central capsule is lobed ; see Model l(i in Case. 



Gallery. IV. Phaeodaria (Models 17, 18), with a double-walled central 



capsule with a few large orifices, and surrounded by dark brown 

 pigment. The skeleton of Ai/Josphrrra (Model 17) is formed entirely 

 of tubes of silex, which join to form a spherical lattice with triangular 

 meshes, a tube with verticils of spines radiating from each node. 

 This species, which lives at the surface in the Mediterranean, has a 

 large shell yV of an inch in diameter. 



Aulacantha (Model 18) has a skeleton formed of hollow siliceous 

 tubes of two kinds, viz., radiating spines and loose needles arranged 

 tangentially on the surface. 



CORTICATA OR INFUSORIA. 



If any animal or vegetable substance be allowed to remain in a 

 vessel of clear water exposed to the air, in a short time tiny specks 

 will be seen swimming about. The organisms appearing in these 

 infusions were termed Infusoria or Infusions Animalcules. The 

 organic matter has simply served as nutriment to the germs of 

 these Animalcules previously existing in the Avater or in the air. 

 Infusoria abound in fresh and stagnant water and also in the sea. 



The organisms grouped under this name differ from the Gymno- 

 myxa, usually in having, in their adult phase, flagella or cilia in place 

 of pseudopods. A cilium is a hair-like organ which can only bend 

 and straighten itself, and which only acts in unison with other 

 cilia. A flagellum acts independently, and with a lashing to and 

 fro movement. 



The Corticata may be roughly divided into four groups : Sporo- 

 zoa, Flagellata, Ciliata, and Acinetaria. 



Sporozoa. 



The Sporozoa are parasitic organisms which live on the juices of 

 other animals, and accordingly, in their adult phase, are devoid of 

 cilia or flagella, having no need for these organs. 



Porospora {Gregarina) gigantea, see Plate YIII. in the Case, from 

 the intestine of the Lobster, has an elongated worm-like body with 

 two segments. The elongated body becomes a spherical cyst, the 

 contents of which break up into thick coated spores ; on the rupture 

 of a spore, an AmrehaAWiQ body is liberated, which develops into a 

 Gregarina. 



