66 



stomach is a gelatinous rod, the rrystalline Style (fig-. 36). 

 In dissections it seems to fill the whole lumen of the 

 alimentary canal at this point, though belonging, as 

 pointed out, to the one compartment, for microscopic 

 sections are necessary to see the separating ridges. 

 Pecten shows a primitive condition in that the style lies 

 in the intestine, but other forms are known connecting 

 this with the complete separation of a crystalline style sac, 

 appended to the stomach. There has been a great amount 

 of discussion Avith regard to the origin and function of the 

 crystalline style, almost every writer formulating a new 

 theory, one or two of which will be considered here. The 

 style has been regarded: — (1) As playing a part in the 

 act of generation (von Heide, Cailliaud); (2) as a 

 rudiment of the radular sac of the Glossophora (Balfour) ; 

 (3) as acting mechanically upon the food under the action 

 of the digestive fluids (]\Iilne Edwards), or serving to briug 

 the food particles between the style and the dense cilia of 

 the epithelium (Sabatier) ; (4) as preventing the food 

 from passing too quickly through the alimentary canal 

 before it has time to digest (Kellogg) ; (5) as a reserve 

 food material (Hazay, Haseloff; (24 and 25); (6) as an 

 excretion (Claus) ; (7) as lubricating the undigested food 

 particles passing through the intestine (Barrois) (23): 

 (8) as an active digestive ferment (Mitra) (26). 



In Pecten maxinms the style is large, sometimes 

 attaining a length of three inches. It is circular in 

 transverse section, and widest near the stomach into 

 which it protrudes. From here it tapers to a point near 

 the end of the descending limb of the intestine. The 

 upper end is sometimes rounded and enlarged, forming a 

 knob ; at other times it is connected with the gelatinous 

 lining of the stomach, and it seems certain that this 

 " fleche tricuspide " and the crystalline stylo are 



