152 M. E. Penard's Notes on some Ueliozoa. 



pletely immersed in the mucilage, arrive at the top before the 

 radial spicules, although after the complete closure of the 

 mucilaginous arch. It is very interesting to see the scales 

 advance, one after the other, in this hyaline envelope, in which 

 they seem to swim, as it were in mid water, as if by a move- 

 ment proper to them ; the radial spicules, having their base 

 only immersed in this envelope, appear to have more resist- 

 ance to overcome and arrive at the top more slowly ; never- 

 theless they reach it, and, after a moment of confusion, resume 

 their relative positions, and the Acanthocystis is then again 

 completely covered by its coat of mail, and an observer 

 coming upon it at this moment might wonder by what means 

 so large a prey could have penetrated beneath the membrane. 

 The whole phenomenon scarcely lasts more than a minute. 



As to the kind of nourishment of the Heliozoa, this is 

 variable according to the medium ; we see some which are 

 stuffed with microscopic Algas, Diatomeas, Desmidieas, &c. ; 

 but in general they seem to prefer to capture small animals, 

 Monads, Vorticellae, Rotifera, &c. Actinophrys, in particular, 

 consumes an incredible number of the latter, and does not 

 always capture them without trouble. 



There is much more to be said upon the physiology and 

 constitution of the Heliozoa. I have not mentioned the bodies 

 of different nature contained in the internal plasma, such as 

 grains of starch, chlorophyll, &c, nor the phenomena of 

 multiplication (fission, conjugation, budding, spores), nor the 

 siliceous cysts into which the animals withdraw, nor the 

 colonies which certain species like to form. All this would 

 lead us rather too far *. I prefer at present to add a few 

 words upon certain organisms which may show us points of 

 approximation between the Heliozoa on the one hand and 

 the Monera, Amoebae, and even the Flagellata on the other. 



The first of these organisms is Vampyrella spirogyrce of 

 Cienkowski. Hiickel has classed the Vampyrelke among the 

 Monera, or Rhizopods destitute alike of nucleus and of con- 

 tractile vesicle ; of late, indeed, very numerous grains of chro- 

 matine or of nuclear substance have been discovered in several 

 organisms which had previously passed as devoid of nucleus ; 



* 1 would nevertheless revert to certain very brilliant blue grains, 

 sometimes very large, enclosed within the body of the Acanthocystides, 

 the signification of which I have discussed in the second part of my 

 memoir on the Heliozoa (Arch, de Biologie, tome ix.j. For some time 

 1 have come to the conclusion that we had to do here simply with grains 

 of starch. Now, a few days ago, having opened a glycerine-preparation 

 in which I preserved one of these large grains, I treated the latter with 

 iodine, and saw it immediately acquire a hue violet colour. It is there- 

 fore starch, and my first suppositious were erroneous. 



