COTHURNIA. 151 



the points of the opposite uncus when closed."* 



There is no connection between the Limnias and 

 her tube, except that of simple adhesion, wliicli 

 takes place by means of the end of the foot-stalks. 

 In a former chapter we have described an inter- 

 esting relation of the Vorticella, the Cothnrnia, 

 whose elegant crystal vases form a very artistic 

 abode, characterized by possessing a distinct foot. 

 Other species of the same family inhabit vases which 

 have no foot or stalk, or live in gelatinous sheaths 

 less accurately fashioned. Sometimes these creatures 

 are obliging enough to conform to the specific de- 

 scriptions which eminent naturalists have given of 

 them, and also to the characters Avhich the authorities 

 have assigned to the different genera in which they 

 have been grouped, but the microscopist will often 

 meet with difficulties in the way of classification. 

 The simplest plan is to consider the group of 

 Vorticella-like animals which inhabit tubes or 

 sheaths, as belonging to the A^orticella family; but 

 it is common to give them a separate name, and 

 designate them as Ophrydhw^ or Vaginifera^ sub- 

 divided into genera, to which characteristics are 

 assigned that do not exactly fit a curious assemblage 

 of creatures, that were developed in the water of 

 this month's collections. 



* The term uncus, ramus, etc., have been explained in chapter 

 II, page 37. 



