98 SOME WONDERS OF THE SEA. 



canals terminate in a wide vessel which runs round the 

 edge of the disc. Here, then, is the digestive apparatus, 

 showing a distinct advance on the animals of the sponge 

 and coral, in which no such apparatus can be discovered. 



Arranged round the edge of the disk are eight little 

 brown spots, which are considered by Ehrenberg to be 

 eyes, and indeed the Naked-eyed Jelly Fishes (alias the 

 " Gymnophthalmic Medusifonn Coelenterata " ) were 

 formed into a distinct group. But I cannot accept these 

 spots as eyes, and think that Ehrenberg was as hasty in 

 considering them as such as he was in describing and 

 figuring his so-called " Polygastric," i.e. many-stomached, 

 "Infusoria." The many stomachs with their connecting 

 tubes are plain enough in his figures, but no one except 

 himself has succeeded in seeing them in the living objects. 

 Professor Eymer Jones failed to find them, though he 

 employed one of Eoss's best microscopes, an instrument 

 of far clearer definition than that used by Ehrenberg 

 when writing his treatises ; and even after inspecting the 

 preparations made by that investigator he still retained 

 his opinion. 



Then other naturalists have credited the Medusae with 

 ears as well as eyes, asserting that certain organs situated 

 at the base of the filaments surrounding the edge of the 

 disc perform the function of ears. These organs are 

 very small, scarcely exceeding the five-hundredth of an 

 inch in diameter, and are irregular in number. 



When examined with a microscope, each of these 

 organs is seen to be a spherical sac or vesicle, containing 



