166 MARVELS OF PONU-LIFE. 



tlie most refined preparation of the dissecting needle, 

 for it is composed of a bundle of elementary fibres, 

 totally separate from one another through their 

 entire course." He further adds, ''The fibres of the 

 great retractor muscle are distinctly marked by 

 transverse stride; — a condition, however, which is 

 not at all times equally perceptible, and some of 

 our best observers have denied to the Polyzoon the 

 existence of striated fibre." 



AVe can confirm the fact of this sort of fibre being 

 present, but we fancy a reader not versed in the 

 mysteries of physiology, exclaiming, 'What does it 

 matter whether his fibres are striped or not?' It 

 does however matter a great deal ; and if Pluma- 

 tella could hear Dr. Allman lecture upon its structure, 

 it would be proud to find its muscles of the most 

 aristocratic sort. ^luscles in the highest animals 

 are composed of fasciculi^ or little bundles of fibres, 

 separated into still smaller bundles, which are again 

 separable into single or ultimate fibres, which are 

 of two kinds. One exhibits transverse marks or 

 striae, and the other does not. The first is the 

 structure of muscles obedient to the will; the last 

 of muscles belonging to the purely organic life, over 

 which the will has no control. The first kind of 

 muscles are usually excited to action by nerves; 

 the last have their contractility, which is an inherent 

 property of muscular fibre, excited by stimuli, that 



