112 BULLETIN OF THE BUREAU OF FISHERIES. 



two fibers touch each other a double row of droplets slightly separated can be easily 

 distinguished. The separating line, of course, is the section through the sarcolemma. 

 The largest fat droplets in this series under the sarcolemma measure as much as 2 /< 

 in diameter. Often the droplets are slightly compressed, evidently by the pressure of 

 the sarcolemma, since the radial diameter is a little less than the diameter tangent to 

 the fiber. 



Taking the pink fibers as a whole it seems that in the better specimens the liposomic 

 fat is present in greater number of droplets, also in larger droplets, than in the poorest 

 specimens from Warrendale (compare fig. 10 and 11). Certainly this fat is greater 

 than in no. 125 and no. 126. In fact, the comparison is close to those fish which have 

 the highest quantity of intracellular fat at stations lower down the river. In the poorest 

 fish taken from the spawning grounds the fat is almost completely eliminated both from 

 the intermuscular and intramuscular regions. This is true for fish no. 140, which has 

 the lowest amount of fat observed in the lateral pink muscle. 



The pink muscle fibers themselves are not plump and round in the fish from the 

 spawning ground. On the other hand, they form irregular polygons in cross section. 

 Even the smaller fibers have lost their cylindrical shape. The fibers are more compact 

 and the whole appearance suggests a diminution in volume (fig. 19, pi. xi). 



In teased preparations there is one rather striking deviation from the typical arrange- 

 ment of liposomes, namely, the deep-lying liposomes are no longer in such regular 

 spindle-shaped rows as are found in the normal. The chains have the appearance of 

 broken rows, in which the smaller liposomes are absent, thus giving the chains an irregu- 

 larity that is rather constantly observed in the fish of this station. Those chains that 

 are most definite and least interrupted are clearly located near the surface of the fiber. 

 In the teased material from no. 139 there is a marked difference in the appearance of 

 the liposomes present in the small fibers as compared with the larger. In the larger 

 fibers the chains are less numerous and the droplets in the chains smaller. In this 

 fish the small fibers, 40 to 50 fi in diameter, have very evenly distributed liposomes, 

 the diameters varying from 0.3 to 0.7 /(. In certain fibers of this section there are 

 irregularly placed highly refractive bodies which (1/12 oil immersion) are only lightly 

 stained. These granules are probably associated with an early stage of degeneration. 



These teased fibers also show irregular patches of liposomes over the surface of the 

 fiber and under the sarcolemma. These fat droplets are a trifle larger than those within 

 the sarcoplasm. In salmon no. 140 we still have a small amount of fat under the sarco- 

 lemma. In the larger fibers the intracellular fat is present only in traces, the liposomes 

 being not over 0.2 /i in diameter and in very short, irregular, and scattered chains. In 

 the smaller fibers of the material the number of liposomes is still relatively slight, but 

 the size of the individual liposomes is somewhat larger. Where a liposomic chain is 

 present it is noted that the arrangement of individual liposomes is very irregular, giving 

 the chain the appearance of being broken. 



Caudal pink muscle. — The pink fibers of the caudal region have as nearly no fat 

 as in any specimen examined. The intermuscular fat is completely eliminated, while 

 only a trace of intracellular fat is to be found. The teased preparations show that this 

 trace is made up of definite but tiny liposomes which are only sufiicient in quantity to 

 give a faint stain to the section. Now and then in a fiber near the surface one can note 



