REFORMATION OF THE CRYSTALLINE STYLE 263 



After considering the list of bivalves on our west coast, Mya 

 arenaria, the eastern long-neck clam, was selected as being the 

 only possible species upon which such an operation as contem- 

 plated might be successfully performed. 



In the first place, Mya, by reason of its anatomical features, 

 has proved to be exceptionally well adapted for this kind of 

 experimental work. This favorable structural feature lies in the 

 fact that the style sac is exposed along the ventral surface of the 

 visceral mass for a distance of from 20 to 30 mm. in specimens 

 ranging from medium to large size (figs. 1 to 3). Furthermore, on 

 removing Mya from the mud it will be noticed that, in a very large 

 number of individuals, the mantle lobes are protruding some dis- 

 tance between the gaping edges of the shell. The mantle lobes 

 are fused along their anterior and ventral margins except for a 

 small space through which the foot may be extended. It will 

 also be found in most instances that the visceral mass of the body 

 of the mollusc is pressed closely against the ventrally protruding 

 mantle lobes. 



By cutting the mantle in the midline along the ventral surface 

 for a distance of from 15 to 25 mm. posterior to the pedal opening, 

 the exposed length of the style sac is brought into view. Using 

 fine-pointed scissors, one may easily sever the style sac transversely 

 or longitudinally at the distal extremity or at any level in the 

 exposed length of it. Usually immediately upon the severance of 

 the sac the style will be forced out at the point of division. Oc- 

 casionally the crystalline style will be thrown entirely out of the 

 body by a sharp muscular contraction when the sac is clipped. 

 More often, however, the use of fine-pointed forceps is necessary 

 to draw the style from the sac. 



In the majority of cases I have severed the style sac and style 

 by a transverse cut at from 10 to 20 mm. from the distal extrem- 

 ity (fig. 3) and removed both ends of the style. The entire op- 

 eration requires but a few seconds of time, and in most individuals 

 must be accomplished immediately after the clam has been taken 

 from the mud, as the mantle lobes are soon withdrawn and the 

 valves of the shell tightly closed, rendering the removal of the 

 crystalline style impossible. 



