SECT. ii. INFUSORIA. 73 



extremities ; but it sometimes occurs of a deep red, and 

 in such multitudes as to give the water the appearance 

 of blood. 1 



The Noctiluca miliaris, a luminous inhabitant of the 

 ocean, and the most beautiful of the Infusoria, is dis- 

 tinguished by its comparatively gigantic size, and 

 by its brilliant light, which makes the sea shine 

 like streams of silver in the wake of a ship in a warm 

 summer evening, when they come to the surface in 

 countless multitudes. It is a globular animal like a 

 minute soap bubble, consisting of gelatinous matter, with 



Fig. 106. Noctiluca. 



a firmer exterior, and being about the thirtieth of an 

 inch in diameter, it is visible to the naked eye, when a 

 glass in which it is swimming is held to the light. On 

 one side of the globe there is an indentation, from 

 whence a tail of muscular fibre springs striped with 

 transverse rings, which aids the animal in swimming. 

 At the root of the tail lies the mouth, bordered on one 

 side by a hard dentile lip leading into a funnel-shaped 

 throat, from whence a long flickering cilium is protruded, 

 supposed to be connected with respiration. The throat 



1 Mr. Gosse. 



