The Scallops 



337 



(Figure 65, / and Figure 67, m /). But these folds are 

 muscular, and on the closure of the shell they bend out- 

 ward near one of the lobes or " ears " of the shell on the 

 hinge side, so as to form a short tube-like aperture. 

 Through this tube the jet is driven, and 

 the body, rotating somewhat, is propelled 

 in the opposite direction. Immediately the 

 shell again opens and closes, and another 

 jet is driven out, but this time near the 

 opposite ear of the shell. Again the body 

 is slightly rotated and driven onward at 

 an angle to the first course. Alternately 

 the jets are discharged from near one ear 

 and then the other in rapid succession, and 

 the creature rises from the bottom in a 

 zigzag course until it reaches the surface. 

 This is represented in Figure 66. Con- 

 tractions then ceasing, it settles to the 

 bottom, usually several feet from the 

 starting point. If this performance were 

 repeated many times, a considerable dis- 

 tance might be covered, and it has been 

 assumed that scallops make periodical 

 and concerted migrations from shallow 

 to deep water and back again. 



This, however, almost certainly is not true, though 

 it is commonly believed. No reliable observer has ever 

 asserted that he has seen these migrations. On the other 

 hand, Mr. Belding, who for several years has watched 

 them closely at all seasons where they grow naturally, 

 and who has had the matter of their supposed migrations 

 in mind, writes that they have remained in the same 

 places the year around. The more intelligent of the seal- 



Fig. 65. — Cross 

 section, edge 

 of shell (s) 

 and mantle 



(m) of Pec- 

 ten, e, eye ; 

 /, flap or fold 



extending 

 inward from 

 the edge of 

 the mantle. 



