Fig. 33. — Early plicated stage. View of the right or lower valve. Note 

 the smooth prodissoconch (pd) and dissoconch (d) areas, with the beginning of 

 the sixteen plications (pi) of the adult. There are four teeth (te) on the byssal 

 notch. Actual size, 1,25 millimeters (^/^o of an inch). 



Fig. 34. — Same scallop as in Fig. 33, viewed from left or upper valve. Actual 

 size, 1.25 millimeters (V^o of an inch). 



Fig. 35. — View of the anatomy of a slightly older scallop, size, 1.4 millimeters 

 (lis of an inch), as seen through the right valve. Note primary, secondary and 

 tertiary eyes (e) and tentacles (t). The outer gill (og) has about twenty-five fila- 

 ments, and begins to resemble the inner gill (ig). 



Fig. 36. — View of right or lower valve of same scallop as in Fig. 35. Note 

 the five teeth (te) on the byssal notch (bn) and the beginning of the "ears" (er). 

 The two teeth back of the external border of the byssal groove are older, and have 

 rounded rather than the pointed ends of the last formed teeth. The valves have 

 become nearly equal, the hinge line straight, and the byssal groove (bg) can be 

 traced back to the asymmetrical prodissoconch. Actual size, 1.4 miUimeters ('As 

 of an inch) . 



Fig. 37. — View of upper left valve of same scallop as in Figs. 35 and 36 Actual 

 size. 1.4 millimeters (^As of an inch). 



