306 NOTES ON SOME CANADIAN INFUSORIA. 



forms described as belonging to the genus. It was originated by 

 Dujardin for the reception of S. rugosa, and Perty described another 

 form as S. patula. Lachmann, 1 however, disputes both these identi- 

 fications, regarding the forms as being merely recently attached im- 

 mature Vorticellce, and admits to the genus only two forms discovei'ed 

 by himself, viz. : S. limacina attached to small Planorbis, and 

 S. physarum attached to Physa fontinalis. Kent, in his Manual of 

 Infusoria, refers two other forms to this genus. Fromentel described 

 a form as S. rugosa, from which, however, it differed in possessing 

 three contractile vesicles, and a very short footstalk ; this Kent 

 terms S. Fromentelli. W Udekem's Gerda inclinans he also places 

 in this genus, the discoverer being somewhat undecided where it be- 

 longed, having described it as belonging to the closely allied genus 

 Gerda, while expressing a doubt whether it might not be referred to 

 Dujardin's Scyphidia, or to an immature form of his own Epistylis 

 tubificis. The form I had under observation (PL Fig. 2.) presented 

 a very close resemblance to this, differing, however, in some points 

 from Kent's description. Unfortunately, I only met with a single 

 example. This measured 0.075 mm., and was over three times as 

 long as broad. The adherent disc I was unable to see, as the ex- 

 tremity of the foot was constantly concealed among conferva?. It 

 tapers considerably posteriorly, and the body presents a fine trans- 

 verse striation. The ciliary disc is elevated somewhat above the 

 peristome, is inserted somewhat obliquely, and is capable of retrac- 

 tion. The mouth occupies the other half of the peristome, which is 

 furnished with a few bristle-like cilia. The ciliated pharynx leads 

 down from the mouth towards the centre of the body. Immediately 

 beneath the edge of the peristome and below the ciliary dise is the 

 single contractile vesicle (c. v.), while below it was a granular ovoid 

 body (n.), corresponding with which was a similar structure on the 

 other side of the pharynx. I was not able to distinguish any con- 

 nection between these two bodies, but imagine them to be portions 

 of the nucleus. According to Kent's description, D' Udekem's form 

 differs from mine in the comparative length and breadth, in the 

 smoothness of the cuticle, and in the snout-like projection of the 

 anterior margin when contracted. He also describes the animalcule 

 as being bent to one side when in the contracted state, and trans- 

 criber der Organisation der Infusiorien, insbesondere der Vorticellinen lluller's Archiv. 1856. 



