THE HYALEA. 149 



teeth, set in a fleshy base, and so arranged as to be 

 capable of seizing prey, and dragging it into the mouth. 

 Cuvier regarded the oars of this animal not only as 

 organs of locomotion, but as a respiratory apparatus : 

 the correctness of this view is denied by Eschricht, 

 and we are, therefore, doubtful as to the laboratory in 

 which the circulating fluid undergoes its necessary aera- 

 tion. Much more, in the economy and structure of this 

 mollusk, remains to be cleared up. In this slight sketch 

 of the Clio borealis, no one can fail to behold the power 

 of the Creator, who, in the minutest, as in the hugest 

 of living beings, displays infinite wisdom, adapted to 

 overwhelm us with wonder and admiration. 



In the Hyalea there are two large wings, but no tenta- 

 cula ; the body is covered with a mantle, having a fissure 

 at the sides ; at the bottom is lodged the aerating 

 apparatus, a circle of vascular leaflets. The mantle 

 is invested in a shell, which has a corresponding open- 

 ing at the sides ; its ventral face is very convex, its 

 dorsal surface flat, and longer than the other ; present- 

 ing at its posterior part, on the transverse line, where 

 it is united to the other, three sharp tooth-Uke projec- 

 tions. From the lateral fissures of this shell the living 

 animal can protrude certain processes, the productions of 

 the mantle. One species, the Hyalea cornea of Lamarck, 



