68 



The period for which he was elected had noAv nearly ex- 

 pired, and he understood that it was the intention of some 

 members to support a motion for the repeal of the law which 

 thus operated against his re-election. He wished, however, in 

 order to prevent any mistake on this matter, to state that he 

 did not intend to offer himself again as a candidate. He had 

 received the office on the condition that he was to hold it only 

 for five years, and he now thought that he was called upon to 

 relinquish it absolutely into the hands of the Academy, and 

 would not, therefore, offer himself for re-election. 



Mr. Donovan read a paper, entitled, " Suggestions for the 

 Improvement of Lighthouses." 



Professor Alhnan read a paper on the Structure of the 

 Muscular Fibre in the Polyzoa. 



" The muscles of the polyzoa are especially interesting in a 

 physiological point of view, for they seem to present us with an 

 example of true muscular tissue reduced to its simplest and 

 essential form. A muscle may, indeed, in these animals, be 

 viewed as a beautiful dissection, far surpassing the most refined 

 preparation of the dissecting knife, for it is composed of a 

 bundle of elementary fibres, totally separate from one another 

 through their entire course. These fibres are distinctly marked 

 with transverse stria?, a condition, however, which is not at 

 all times equally perceptible, and some of our best observers 

 have denied to the polyzoa the existence of striated fibre. At 

 the meeting of the British Association at Southampton I made 

 known its occurrence in Cristatella, and have since, byrepeated 

 observation, satisfied myself of the striated condition of the 

 fibre in the great retractor muscle in all the other fresh-water 

 genera. In Paludicella I have seen this state beautifully 

 marked through the pellucid cell, in the whole extent of the 

 retractor muscle, while the fibres were on the stretch in the ex- 

 serted condition of the polypide; and in all the other genera i* 



