



Microns 



60 







Figure 150. — Longitudinal section of tlie adductor muscle 

 of C. t'lrginicn where the muscle fibers are attached to the 

 shell. Note the holding epithelium and the cement layer 

 which in the upper part of tlie illustration is separated 

 from the epithelium and turned over. The decalcified 

 shell is out of the field of view. The cement film is 

 partially detached at the upper half of the preparation 

 and twisted exposing its surface facing the shell; the 

 width of the upper part of the film corresponds to the 

 thickness of the section. Kahle. Hematoxylin-eosin. 



drilled in the valves. In another set of experi- 

 ments the muscles of oysters with the shells 

 attached to them were immersed in the solution 

 of collagenase and were kept at a temperattire of 

 24° to 25° C. for 24 to 48 hours. Solutions of 

 trypsin and phosphate buffer alone, without 

 collagenase, were used for control experiments. 

 In all cases the muscles treated with collagenase 

 became detached within 36 hours. In the con- 

 trols they remained attached to the shells (fig. 

 152). 



Millimeters 



0.3 



Figure 1.51. — Cross section of the visceral mass of C. vir- 

 ginica near the adductor muscle. Notice the gradual 

 change of typical mantle epithelium (left side) into 

 tiolding epithelium covering the adductor muscle. The 

 shell is not shown. Kahle, hematoxylin-eosin. 



CHEMICAL COMPOSITION OF THE 

 ADDUCTOR MUSCLE 



The chemistry of the adductor muscle of oysters 

 has received less attention than that of the mus- 

 cles of clams, scallops, and sea mussels. Probably 

 the differences in the chemical composition of the 

 muscles of various marine lamellibranchs are not 

 of fundamental nature, although the proportion 

 of various components may vary greatly between 

 the species and even within moUusks of the same 

 species living in difi'erent environments. Older 

 reviews dealing with the comparative physiology 

 of the adductor muscle make no distinction be- 



THE ADDUCTOR MUSCLE 



161 



