320 PROGRESS OF MICROSCOPICAL SCIENCE. ['journal S^rsTa' 



fossil Sigillarian forests of Nova Scotia, and also iu tlic mineral charcoal 

 of the coal-beds, Tliis was illustrated by descrijjtions of structures 

 occurring in erect and j)rostrate Sigillariee, on the surface of Stern- 

 bergia casts, and in the coal itself. 



The Relation of Vorticella to Adinophrys. — In a letter published 

 in 'Scientific Opinion' (May 11th) Mr. C. Staniland Wake records 

 some interesting observations on this subject. Having described his 

 method of making a number of organic infusions, and stating the 

 nature of the bodies subsequently found in them, ho says : — The 

 infusions produced, moreover, bodies of a circular form, which I have 

 now little doubt were encysted forms of Vorticella. In addition to 

 these, however, were a niunber of larger bodies of different shapes, the 

 natiu'e of which I could not for some time determine. That they were 

 animal organisms I did not doubt. Their appearance — that of a nearly 

 cii'cular and nucleated cell, with an outer faintly-defined rim — was 

 sufficient to induce this belief. No motion was at first noticeable, but 

 I soon found that the shape of these bodies altered, and I at once set 

 them down as having an amoebal character. This idea appeared to be 

 confirmed by the fact that free-moving amoebaB were also present in 

 these infusions. I have not studied the changes of Vorticella, and 

 therefore I was much surprised, on examining these infusions some 

 days later, to find a great number of these forms in full activity. What 

 is the explanation of this fact ? It was soon made apparent by a re- 

 ference to Pritchard's fine work on Infusoria. At plate 27, Pritchard 

 gives several figures of Vorticella microstoma, this being, I have no 

 doubt, the form which was so j^lentiful in my infusions. On plate 23, 

 moreover, several forms are figured, which I at once recognized as 

 those which I had supposed to be amoebal. In Pritchard these are 

 classed with Actinophrys, but they are described as having been figured 

 by Stein as phases in the develoj)ment of Vorticella microstoma. Eight 

 of these phases are given by Stein, and of these Nos. 1 and 2 in 

 Pritchard almost perfectly represent the forms produced in my 

 infusions. In addition, however, to Vorticella microstoma were several 

 other analogous forms, among them one much resembling ActinopJirys 

 linguifera or Acineta (Pritchard, pi. 23, fig. 17). Since I noted the 

 above facts, most of the Vorticella have disappeared, and the circular 

 bodies have increased very largely in number, the smaller ones being 

 extremely numerous. These bodies are nearly always associated with 

 the fungoid matter. They evidently increase in size, and seem to me 

 to be phases of the encysting process of Vorticella microstoma, as 

 figured by Dr. Carpenter in his work on the Microscope. In addition 

 to the infusoria referred to, the infusions now contain several other 

 forms, among them Kolpoda cucullus. 



