o(30 î. iiCEbA : 



say with certainty tliut, at least in the lavva^ Htuclietl 1)y nie, 

 there existed no snch fnnnel-system nor any sneh free eonnnuni- 

 eation between the collar cavity and the nephridial canals. The 

 same negative resnlt was also reached l)y nie in my examination 

 of the just metamorphosed larva of tyjie A. Thus in tig. 0-4/ 

 >vhicli is drawn from a section through the tip of the nephridium, 

 the excretory cells [exec.) still remain compactly grouped on the 

 1)1 ind ti]) of the canal {m'p.c), hut are not traversed by any sort 

 of canal-systems. 



Muscular Sydcm. The muscular system of Adinotrocha re- 

 mains in a low state of development, which may account for the 

 fact that most previous observers have paid no particular atten- 

 tion to it. It was therefore of much interest to discover two pairs 

 of t(jlerably well developed muscles, which had hitherto remained 

 apparently unknown. They show a strong resemblance to the 

 retractor muscles which have been known in many forms of 

 Trocho2?hora larvœ. 



Though the longitudinal and circular muscles of the liody 

 wall may be observed with tolerable distinctness in the living larva, 

 they are usually very poorly preserved after hardening. They are 

 all subdermal in position and very delicate in structure, so that 

 as a rule they can not be satisfactorily distinguished from the 

 underlying peritoneal layci'. However, in certain jn'cparalions of 

 the entire larva the circulai- muscles of the upper and lower 

 walls of the preoral lobe and of the trunk body wall could he 

 detected as line deeply stained fibres. In the same way the 

 lonuitudinal muscles of the collar wall, esiK'ciallv in the larva, 

 of type V, were fairly traceable. The larva of that ty})e also 

 exhibited a peculiar arrangement of the circular muscles of the 

 trunk, in that these formed four, e(iuidistaiit, hMgitudinal series 



