38 Mr. R. Valleiitin on the 



airangeraeut and distribution of the muscles in tlicsc two 

 species. 



Prof. Williamson (5) ?ays, " Distinct muscular bands occur 

 at intervals in the common tegument, concentrically encircling 

 the entire organism. Their action is easily observed. Still 

 larger and more distinct fasculi run lengthwise ; some of these 

 proceed from the upper part of the visceral cavity to the base 

 of the tail or peduncle, where they are inserted into a thick- 

 ened portion of the integument. Others, taking their rise 

 from the various parts of the body, proceed along the caudal 

 prolongation, and are inserted into a little concavo-convex 

 body at its extremity." 



Dr. Hudson says, " The longitudinal muscles, as in the 

 Flosculariada^, run up the foot to its junction with the trunk, 

 where they are fastened. They then cross the trunk till 

 they reach the neck, where they are again fastened; and as 

 they reach the head they divide into branches, which cross 

 the lobes of the corona, and, by their contraction, furl it. 

 Transverse muscles, imbedded in the integuments, encircle the 

 trunk ; and, by the compression of the bodj'-fluids, drive out 

 and unfurl the corona, just as in Flosailaria." 



M. Joliet gives, according to my oltservations, the most 

 exact description of the arrangement and number of muscles 

 in this species. He says, under this heading, " H se compose 

 principalcment de huit cordons musculaires, qui vont s'inserer, 

 d'une part, a I'extremite de la queue qu'ils parcourcnt dans 

 toute sa longueur, et de I'autre symetriquement a difierents 

 niveaux sur la face ventrale, sur la face dorsale, et sur les 

 cotes du corps." 



On reference to fig. 7 and the accompanying explanation 

 one cannot fail to notice that the muscles in the foot of this 

 species are arranged in a manner distinctly different to that 

 of any ordinary tube-dwelling Rotifer ; and, further, the 

 muscles present in transverse section an almost crescentric 

 outline, appearing to be united by sarcolemma only when 

 viewed in longitudinal section. It will also be noticed that 

 the muscles are placed some distance from the cuticle and not 

 arranged in any order, but appear to move freely in the large 

 body-cavity space in the foot. As to whether or no these 

 features are in any way caused by the reagents used I am 

 unable to determine ; still all my sections agree as to these 

 points. Posteriorly, owing to the tapering form of the foot, 

 the muscles tend to converge, and in the region of the poste- 

 rior third they unite and form the attached extremity. At 

 the junction of the foot with the trunk the muscles form the 

 usual four jiairs, and, continuing anteriorly, remain unaltered 



