1880.] 



MICROSCOPICAL JOURNAL. 



or stained with some coloring fluid. 

 During complete contraction, it 

 shortens, thickens, and becomes 

 much folded upon itself. 



The contractile vesicle is seen as 

 a clear, circular spot, located near 

 one side, and just below the junction 

 of the upper with the midcile third 

 of the body. In most of the indi- 

 viduals observed, its systole and 

 diastole occurred about ten times 

 in a minute. When about to trans- 

 form to the free state, these animals 

 begin to contract to the pyriform 

 shape more frequently ; they ex- 

 tend themselves more and more 

 slowly, until finally the pyriform 

 or oval shape is retained, the animal 

 remaining quiet with the peristome 

 and disc inverted, but the cilia of 

 the oesophagus still active. 



A posterior circle of cilia begins 

 to develop, in fact may begin to 

 form before the pyriform shape is 

 permanently assumed ; this ring of 

 cilia is located around the dilated 

 portion of the body. After re- 

 maining in this condition for per- 

 haps ten, twenty or thirty miimtes, 

 the animal seemingly becomes rest- 

 less, and endeavors, by active move- 

 ments of the body, produced by 

 the posterior cilia, to twist itself free, 

 and finally, after strenuous efforts, 

 it breaks loose, and rapidly swims 

 off, usually swimming anteriorly by 

 means of the newly-developed cilia, 

 although it has been observed to 

 swim for a short distance with the 

 other extremity foremost. 



The free condition is assumed 

 without any further division of the 

 stalk, and the animals do not un- 

 dergo development to the second 

 stage, without the formation of the 

 posterior crown of cilia, yet they 

 sometimes become detached before 

 this condition is attained. In 

 one instance, when the animal 

 was subjected to slight pressure, a 

 sort of fold or invagination of the 



cuticle appeared to surround the 

 body transversely, near the upper 

 part, and slowly moved downward 

 to the extremity attached to the 

 stem, when the animal became 

 quickly disjointed and moved away. 



After assuming the free condi- 

 tion, the animal is cylindrical, the 

 length about twice or nearly three 

 times the average diameter ; the 

 anterior cilia are still inverted; 

 the oesophagal cilia may yet be 

 seen in action ; the diameter is 

 greatest where the posterior circlet 

 of cilia is attached, and from this 

 circlet the body gradually tapers to 

 the point where it was detached 

 from the stalk. After some time, 

 however, it appears to become 

 more rounded. The upper end of 

 the disjointed stalk may be readily 

 seen. 



After swimming about for a 

 short time, these free individuals 

 were observed to attach themselves 

 to the glass slide ; in this case the 

 extremity which was formerly free 

 remained so, the other end becom- 

 ing again attached, losing the 

 circlet of cilia. In this state the 

 body slowly assumes the appear- 

 ance presented when extended pre- 

 vious to these changes, but it is 

 nearly globular during active con- 

 traction, which occurs upon the 

 slightest irritation or disturbance; 

 it gradually lengthens and assumes 

 a condition of activity, the invert- 

 ed cilia of the peristome and disc 

 slowly everting again, the posterior 

 cilia become less and less active, at 

 last entirely disappear. 



To recapitulate, the generic and 

 specific characters of this animal 

 are the following : Lorica gelati- 

 nous ; animals radiately clustered 

 in numbers varying from one hun- 

 dred to four or five hundred or 

 even a thousand ; each one attached 

 by a long, non-contractile stalk, 

 which penetrates to the interior of 



