368 



Greenfield on the day of the public sale, and purchased a 

 large part of the collection for the Society, for the sum of 

 #1400. 



On motion of Dr. Durkee, it was voted that the report be 

 accepted, and the Committee be requested to continue their 

 efforts to raise, by subscription, a sum sufficient to meet the 

 payment for which they had become responsible. 



Dr. W. I. Burnett presented the following communication 

 on the nature and character of Muscular tissue, as illustrated 

 by its development and minute structure. 



The beautiful form of this tissue, as occurring in the Thorax 

 of insects, and which was discussed at the last meeting, has led 

 to some further research upon the whole subject of the histology 

 of muscle. This delicate, and what may be termed, fibrillar 

 form of striated muscle, mentioned at the last meeting, is found 

 to occur in the other Articulata, beside the Insecta. Perhaps 

 it is most prominent in the Crustacea, and particularly in the 

 Entomostraca. Thus, in the Argulina and Caligina, the muscles 

 show this structure even more perfectly than in Insects. By the 

 addition of water, these fibrillin? separate into their constituents, 

 and then the discs, of which they are composed, may be studied 

 separately. With the use of the highest and best microscopic 

 powers, these discs appear as entirely homogeneous, solid bodies. 

 As the fibrilla has no sarcolemma, it is unknown by what means 

 these discs are retained in place in the fibrilla ; but they are 

 arranged in piles, with a small interspace between every two, 

 which is the light space seen when the fibrilla is examined with 

 high and good lenses. The physical phenomenon of the con- 

 traction of these muscular fibrillse, seems to consist merely in the 

 crowding of these discs together, the light intervening space dis- 

 appearing, whereby the fibrilla is shortened. 



In muscular tissue, the fibrilla is a secondary or an artificial 

 product; the ^^re is the true embryological formation. This is 



