70 TESTACEA. 



shell. But, by allowing them to remain a day or two in stale water, and 

 then replenishing the vessel with fresh water, they quickly expand and 

 begin to crawl. 



They dwell in multitudes in Lochend ; some under stones. Many 

 among the folds of the yellow Iris, and, on drawing up the roots, an 

 hundred empty shells, along with some living specimens, may be readily 

 obtained. 



Plate XIV. 



Fig. ] . Ci/clas cornea, in motion 



2. Spawn, enlarged. 



3. The same, enlarged. 



5. Tellina.— Plate XVII., Fig. 8. 



A distinct illustration is afforded of the active powers of some of the 

 lower animals by this subject. 



The shell, rudely oval, might be circumscribed by a broad ellipse, 

 extending an inch. The edges are smooth : the colour almost white. 

 The animal, also white, bears considerable resemblance to the pi-eceding ; 

 the anterior part, protruding in a conical form, terminates by two orifices, 

 scarcely forking asunder ; one of them fringed ; in the opposite extremity, 

 prolonged as a slender conical foot. The total extent of this animal is 

 about two inches. It is to be recollected that the whole body of the 

 creatures inhabiting bivalves is commonly contracted, and tlie shell closed 

 firmly around it. 



But this latter extensile organization is not employed as a foot, 

 according to the nature of many other bivalves, which open very gradu- 

 ally, and slowly protrude their parts. Here, the white extremity, as it 

 issues, testifies a very active searching motion. Stretching to the utmost, 

 the animal suddenly springs away amidst the water. Its motions are 

 vehement and instantaneous, so that it seems i-eady to spring out of the 

 vessel. 



