AMPHIZONELLA VIOLACEA. 157 



matter, a varying number of clear vacuoles and a 

 single round nucleus. The pseudopodia straight, blunt, 

 digitate, and extending radially from the orifice. Move- 

 ments of the organism habitually sluggish. 



Dimensions: Average diameter 160 /a (Penard). 



Ireland, 1877 {W. Archer). 



This organism, since Greeff's description of it was 

 first published in Schulz's ArcJiiv, has been the subject 

 of much controversy, some authors maintaining that it 

 properly belongs to the genus Gochliopodium Hertw. 

 & Less., whilst others have confounded it with the 

 more recently discovered Zonomyxa violacea Niisslin. 



As Greeff pointed out, the outer envelope of A. 

 violacea is of a character which renders it liable to be 

 mistaken for a band of hyaline ectosarc, but upon 

 close examination it will be found to represent an in- 

 dependent structure carried round the lateral margin 

 of the test and organically connected with it. Its 

 differentiation from the protoplasmic substance has 

 been demonstrated by the use of reagents. The violet 

 tint is said to be very evanescent ; it readily disappears 

 under the action of acids. 



Penard in " Notes sur quelques Sarcodines," in 

 'Rev. Suisse de Zool.' (1906), makes an exhaustive 

 comparison of the two organisms, Amphizonella violacea 

 Greeff, and Zonomyxa violacea, Niisslin, and establishes 

 their mutual independence. Not the least important 

 difference between them — apart from the difference of 

 contour — is the uninuclear character of the one and 

 the multinuclear character of the other. 



Genus 31. ZONOMYXA Nusslin, 1882. 



Zonomyxa Nusslin in Zeits. wiss. Zool. XL, 4 (1882), p. 697. 



Body roundish pyriform, invested by a supple chiti- 

 noid membrane (without the clear mucilaginous 

 envelope characteristic of the preceding genus) , violet- 



