OVA OF THE STEPHANOCEROS. 67 



organs probably perform the function of gills, or bran- 

 chics. 



There are visible muscles, by which the motions . of 

 the body are effected. The stomach is ample, and situ- 

 ated immediately beneath the mouth: it generally 

 contains Monads and other minute Infusoria, (pi. ix, 

 fig. 1, d). There are two jaws, armed at their ex- 

 tremities with four free teeth, the action of which is 

 very discernible, (pi. ix, fig. 1, c, and lign. 7, p. 56), 

 and it is amusing to watch the movements of these 

 dental organs when tearing the food. Ehrenberg men- 

 tions having seen a Stentor grasped by the tentacula ; 

 and I once witnessed a similar capture. 



The Stephanoceros is ovo- viviparous ; that is, it 

 increases by eggs which are hatched ere they escape 

 from the sheath. A cluster of eggs may generally be 

 seen in the ovisac, and one or Jwo advancing to ma- 

 turity, (pi. x). 



THE DEVELOPMENT OF THE YOUNG IN THE STE- 

 PHANOCEROS. As the progressive development of the 

 eggs and young of the Stephanoceros has not, I believe, 

 been made the subject of accurate observation, I shall 

 here introduce a few particulars which came under my 

 notice when investigating the organisation of this ani- 

 malcule in the spring and summer of 1843. 



F2 



