ITS STRUCTURE. 255 



various directions. I could not detect the least trace 

 of ciliary action on it, or indeed on any part of the 

 surface. 



Within the sac, which appears to have thin walls, 

 there is a mass of viscera suspended from the bottom 

 of the furrow, and hanging down in a gradually taper- 

 ing cone nearly to the bottom of the interior, to which 

 in some specimens (not in all), the mass was tied by 

 a slender thread or ligament. Among the viscera 

 were two or three globular organs, one of which was 

 yellow, and appeared larger and more filled with food, 

 or less and more empty, in different degrees, in dif- 

 ferent individuals. I should have little hesitation in 

 pronouncing this, from its resemblance to a similar 

 viscus in the Polyzoa and Kotifera, to be the stomach. 

 The other globose viscera were colourless, but had a 

 turbid nucleus. 



The arrangement and bulk of this mass of viscera 

 vary much in individuals, and in some the Avhole is 

 almost obsolete. In one or two there was an isolated 

 globose viscus far down in the cavity near the bottom. 

 As these specimens were smaller, I thought of the 

 male of Asplanchna, (a Rotiferous genus of which 

 these animals strongly reminded me,) in which the 

 digestive viscera are obsolete, and suggested the pos- 

 sibility of this isolated viscus being a sperm-sac. On 

 pressure, however, to the extent of bursting the viscus, 

 the extruded contents were granular, and I could not 

 trace any Spermatozoa. I believe that it was only 

 the stomach, got loose by the decay or absorption of 

 the connecting membranes, and floating freely in the 

 cavity. Fig. 8 is the representation of one of these- 



