208 TRANSACTIONS LIVERPOOL BIOLOGICAL SOCIETY. 
fectly transparent, and seen singly, colourless; in mass 
the substance is very slightly yellowish. The length, 
when taken from full-grown specimens, varies from 20 to 
26mm. The diameter decreases from above downwards, 
and may be taken as about 1 mm. The proximal 
extremity always projects into the cavity of the stomach, 
and is opaque and slightly frayed; the distal extremity 
does not fill the lumen of the ventral portion of the sheath, 
but remains adherent to one portion of the wall. It is 
firm, somewhat elastic, but breaks easily. | 
Barrois,* in an exhaustive memoir on the Morpho- 
logy and Physiology of the Lamellibranch Style, gives an 
account of the chemical composition and reactions of the 
substance of which it is composed, which may be briefly 
summarized here. Barrois made his analysis and experi- 
ments on the crystalline styles of Cardiuwm edule. The 
style has an average weight of 0°026 grm. It is a colloidal 
substance. A number placed together coalesce to form a 
transparent jelly, which takes the form of the vessel in 
which it is contained. Dried at a temperature of 120°, the 
mass contracts considerably in volume, but still remains 
perfectly transparent and somewhat moist. On ignition a 
small amount of inorganic ash remains. ‘The fresh style 
is rapidly soluble in concentrated hydrochloric acid to a 
bluish solution ; it is slowly soluble in water, forming a 
slightly opaque and viscous solution. Miullon’s reagent 
gives a red colouration in the warm. Treated with copper 
sulphate solution and caustic potash, a fine blue colouration 
is obtained. These reactions indicate the presence of an 
albuminoid substance. 
When the solid styles are boiled with dilute sulphuric 
acid, and the acid solution neutralized and precipitated 
with alcohol, a solution in the latter solvent is obtained. 
* Revue Biologique du Nord de la France. T. I. and IL., 1889—90, 
