CRYSTALLINE STYLE OF LAMELLIBRANCHS 81 



product of epithelial secretion. Eighteen years later, Sabatier 

 (pp. 28, 29) , after an exhaustive study of the histological structure 

 of the epithelium surrounding the style, found that the cells of 

 this region were full of an unusually large number of protoplas- 

 mic granules. He considered that these cells therefore formed 

 a secretory epithelium destined to furnish the stomach with a 

 digestive fluid. Barrois ('89, p. 309) was of the same opinion 

 regarding the origin of the style. 



Haseloff ('88) and Hazay ('81), whose conclusions are given in 

 the historical summary (p. 60) believed that the style was a mass 

 of nutriment transformed in the stomach by the action of the 

 gastric juice and stored in the style sac as a reserve. As their 

 conclusions have been so ably disposed of by Barrois ('89), we 

 need not consider them further than to say that they were based 

 on false deductions, and have no valid evidence to support them. 



Drew ('01, p. 352) says of Nuelula: 



The posterior and part of the lateral walls of the stomach are formed 

 by long and slender epithelial cells that stain but lightly. They se- 

 crete a mucus-like material that stains deeply, and probably corre- 

 sponds to the crystalline style. In adults this structure seldom takes 

 the form of a rod, but in embryos a rod is commonly present. 



Mitra ('01, p. 601) says, regarding the secretion of the style, 



There are grounds for beUeving it is secreted by the so-called liver. 

 The chief ground is that there is in the liver an amylolytic ferment 

 exactly like the ferment of the style. The ferment in the liver behaves 

 exactly as the style ferment does. On the other hand, we could hardly 



detect any amylolytic ferment in the enteric epitheliimi 



There is also another fact which must be allowed to have some force 

 in this connection. It is that yellow pigment cells from the liver are 

 occasionally seen to form the axial zone of freshly formed styles. 



Biederman ('10-' 11) argued from the almost universal pres- 

 ence of ciliated cells in the style-bearing region that, as these 

 could not at the same time be secretory cells, the hepatopancreas 

 was probably the organ of secretion. 



By far the greatest weight of evidence, historically, however, 

 places the seat of origin of the style in the typhlosoles. In forms 

 where these do not occur the secretory activity is confined to a 

 region of cells lying in the wall of the style sac itself. 



ODRNAL OF MORPHOLOGY, VOL. 31, NO. 1 



