278 
ALIMENTARY SYSTEM — CRYSTALLINE STYLE. 
crystalline style. In some species, this sac can be shut off from the 
stomach by a valve, or, as in Utiionidw and other groups, may become 
fused with the initial part of the intestine, communicating therewith 
by a narrow slit. 
The Fl^che-tricuspide or three-pointed body is a firm and gelatinous 
cuticular investment of tlie internal walls of the stomach, especially 
developed towards its pyloric 
end and even continued with- 
in the intestine itself. This 
stomachal coating, which is 
continuous with the crystal- 
line style, especially charac- 
terizes the Pelecypoda, but is 
present in many Gastropods, 
and is secreted by the epithe- 
lium of the stomach, chiefly 
for the protection of its deli- 
cate walls and the secretory 
cellules therein, but in certain 
marine genera this structure 
may become differentiated to form variously shaped masticatory plates. 
Tlie Grystalline Style, formerly supposed to be correlated with the 
absence of mandililes, is a semi-transparent variously shaped rodlet of 
concentric structure, continuous with and of similar consistency to the 
Fleche-tricuspide, of which it is a specialized outgrowth, usually 
projecting freely into the cavity of the stomach from the pyloric coecal 
sac, secreting and containing it. It bears some general resemblance 
to a })estle and mortar, and probably assists 
to more intimately intermi.x the food in 
the stomach with the gastric ferments, 
which are usually poured directly into the f,,.. 555.-Crys..-iiiine style of 
stomach from the digestive gland in those eIuaigTd%ft^^fMoquiii-Ta®n^^^^^^^ 
species possessing the crystalline style, but where the pyloric sac is 
not developed the digestive fluid may be emptied into the plectou, 
whose restricted diameter allows a thorough iiitermi.xture to readily 
take jtlace. The stylet and its extensions being exposed to the action 
of the digestive fluids become softened and partially dissolved, 
furnishing the material for surrounding with a soft glutinous film any 
sharp, angular parficles accidentally swallowed with the food, thus 
f'ui. 5ot. — Median section through Stomach and 
Stylotheca of Donax, showing the Crystalline Style 
in situ and the arrangement of the Fleche-lricuspide 
on the stomach walls, greatly magnified (after Harrois). 
st. stom.ach, with the Fleche-tricuspide f.t. ; a\ 
cesophagus ; i. intestine ; sc. Stylotheca, with the con- 
tained and projecting Crystalline Style c.s. 
