REFOEMATION OF THE CRYSTALLINE STYLE 289 



veal the intestinal wall abundantly supplied with spindle-shaped 

 masses of mucus. These may be traced to the summit of each 

 typhlosole, but are not observed as differentiated masses in the 

 epithelium of the style sac proper. The group of narrow cells of 

 the right typhlosole, under the action of the above stain, gives a 

 solid mucus reaction, while the general epithelium of the style 

 sac gives no mucus reaction whatsoever. 



In cross-sections through the middle region of the style sac 

 stained in mucicarmine, a solid mucus reaction is noted in the 

 group of narrow cells on the border of the right typhlosole. 

 Fusiform clumps of mucus are observed in the groove, but the 

 cells of the general surface of the style sac give no mucus reaction. 



Transverse sections at different levels, stained in toluidin blue, 

 also indicate an abundance of mucus in the right typhlosole, in 

 the groove, and at the apex of the left typhlosole. No mucus 

 reaction is obtained with this stain from the epithelium of the 

 general surface of the style sac. 



Comparing sections of the style sac of Mya arenaria and Schi- 

 zothaerus nuttallii, it will be found that the latter, stained in 

 Delafield's hematoxylin, show the gi-oove and both typhlosoles 

 to be filled with spindle-shaped masses of mucus, while scatter- 

 ing mucus glands are observed among the shorter epithelial cells 

 of the tube. I have not been able to secure such a reaction in 

 Mya arenaria treated with hematoxylin. 



It would seem evident, therefore, from the work of previous 

 investigators and from the actual observation of the position of 

 the newly formed crystalline style, supported by histological 

 evidence, that the typhlosoles supply the material for the sub- 

 stance of this organ, and that the shorter cells with strong cilia 

 assist in molding the crystalline style into its cylindrical form and 

 at the same time rotate it and push it into the stomach. 



8. SUMMARY AND CONCLUSIONS 



1. In Mya arenaria approximately 50 per cent of the individ- 

 uals survive the extraction of the crystalline style by a severance 

 of the style sac. 



THE JOURNAL OF EXPERIMENTAL ZOOLOGY, VOL. 30, NO. 3 



