CRYSTALLINE STYLE OF LAMELLIBRANCHS 91 



color in Cardium during the year, being a deep orange in April, 

 when it was most highly colored. 



Much variation in the consistency of the style was observed 

 in the different species, this difference being correlated with the 

 rapidity with which the structure underwent dissolution. As 

 found in the Unionidae, Mytilus, and Ostrea, it was soft and 

 gelatinous, becoming much firmer in Cardium, Solen, Donax, and 

 Pholas. The brown inner core of food material was held by 

 Barrois to be abnormal. He noted that the style of Pholas never 

 contained such a structure. The coaxial layers in the style of 

 this species were thicker near the center and much thinner 

 toward the periphery, grading from 9 to 35 microns, with an 

 average of about 14 microns. The style of an adult Pholas 

 crispata showed from one hundred to one hundred and ten suc- 

 cessive layers. 



In the cortical layers of the style Barrois found small crystal- 

 line bodies which were insoluble in water and resistant to acetic 

 acid. These were undoubtedly the same structures described 

 by Vulpian ('67) as crystals of calcium oxalate. Since the latter 

 investigator also found uric-acid crystals in some styles, he con- 

 cluded that the crystalline style must have some connection 

 with the excretory function. Similar crystals were described by 

 Hazay ('81), as semitransparent, ruby-colored rhombohedrons. 



I have found such crystals in the styles of Anodonta and 

 Ostrea. They are usually red or jet black, the former resembling 

 in color the lipochrome pigment cells in the integument of the 

 crayfish. These crystalline bodies are not normally present in 

 the style, but appear after partial desiccation of the style 

 substance. 



A fairly complete chemical analysis, made by Lambling, is 

 given by Barrois, '89. The style used was that of Cardium 

 edulis, which in an adult specimen is about 26 mm. long and 

 weighs approximately 0.026 g. 



His analysis of fifty styles gave the following results: 



grams 



Weight of fresh styles 1 .3225 



Weight dried at 120°C 0.1705 



Insoluble mineral matter 0.0025 



Soluble mineral matter 0.0090 



