102 



LUCERNARIyE AND THEIR ALLIES. 



at various anslrs, a part of those of sets numbers one to five. Set number seven 

 has the same relation to the other two camera as that which number six has to the 

 first two mentioned, and crosses the hitter at riglit angles in and about the axis. 

 These two latter sets are the only ones which occupy the axis, the others forming 

 an intricate inclosure about it, the fibres of number four approaching nearest to 

 the centre, and forming a quadrangle between the proximate sides of the four 

 camera;. In point of complexity and regularity of arrangement, combined, there 

 is nothino- iu tlie whole class of Acalephic that can approach what we have here 

 described, and it is to be matched only in a higher class, the Ctenophorae. In the 

 youngest specimen, about one-eighth of an inch across the umbella, the fibres of 

 these sets {/hj. 128, c) are much less numerous than in the full grown animal; in 

 fact those of numbers three and four are not made out. It is remarkable, too, that 

 fibres of numbers one and two penetrate the hollow of the cylindrical muscles. At 

 the extreme posterior end of the peduncle {Jig. 127, c^), where the chondrophys 

 forms a part of the floor of the transverse " adherent disk," the fibres pursue a dif- 

 ferent course, gradually verging around from their position in front until they 

 assume a trend which is at right angles to that, and consequently parallclwise with 

 the longitudinal axis. In this region their arrangement seems to be reduced to 

 the utmost simplicity, all trending uniformly iu the same direction. 



198 (A). As to the mode of origin of these fibre-cells very little can be added 

 to what has been said of those in the undjella proper, except to confirm the view 

 there expressed by referring to their multiple decussation in the peduncle. It is 

 plain that tlie cells of the gastrophragma have nothing in their arrangement upon 

 which so many varied positions of the fibres could be based, all at the same time, 

 and there are certainly no other cellular collections near at hand, but in the mus- 

 cular cords. The all-pervading, hyaline substance, then, is our only resort, from 

 which to derive the fibres that are imbedded in it. Just as the crystal lays down 

 its faces and angles in definite relation to its several axes, so may the less inani- 

 mate, more highly endowed hyaline substance of the chondrophys apportion to 

 each fibre-cell its place and attitude in reference to its fellows, and that, too, with- 

 out going beyond its own boundaries, or self-evident area of activity. 



199. Ilkfohyfj of /he Peduncular Miiscks (^[ 59, 88) (fiff. 116).— The fibrous 

 appearance, which these muscles present under a moderate magnifying power, is 

 deceptive, and is due to the longitudinal folds and not to the visibility of the 

 fibrilla;. The latter, on the contrary, are so excessively transparent and fine as to 

 require a high power and a very clear definition to even so much as detect them. 

 In addition to this there are very serious obstacles in the way of isolating the 

 fibnllic (//;/. 116, r); and these are nothing less than numberless globules or 

 spheroidal cells (J'), which pervade and crowd the tissue. Indeed these cells, 

 varying considerably in size, constitute one-half, at least, of the bulk of the mus- 

 cle ; and by reason of their conspicuity seem to form a purely cellular tissue (.AV- 

 IU) with large intercellular spaces. More careful research revealed the fact that 

 these apparent interspaces are occupied by a close network of anastomosing 

 fibrillar (,//,/. 116, r'). The latter, no doubt, are the true motor agents of the 

 muscle, while the globose cells form the framework for support and\ittachment. 



