162 DESCRIPTION OF [Polygastrica. 



presumption is, that they do not exist externally, as none 

 of the species either swim or produce currents which are 

 perceptible in coloured water. They have a sort of creep- 

 ing or crawling movement, much like eels, and can change 

 their forms, after the manner of the Proteus ; they ap- 

 proximate the Amoeba in other relationships than in respect 

 of their being deficient of the proboscis. At the fore part 

 of the body may be seen two very delicate blackish- 

 coloured spots, analagous to the eyes in the species of 

 other tribes. They are sometimes confounded with the 

 Proteus diffluens of Miiller. All the species are exquisite 

 objects for a deep powered microscope, namely, 460 times. 



140. DISTIGMA? tenax (Proteus, M.) The tenacious 

 Distigma. Body the largest of the genus, proteus-like, 

 at times greatly distended, then as much constricted; eyes 

 rather indistinct ; colour transparent yellow. Found about 

 lemna. Length ] -240th. 



141. DISTIGMA proteus (Proteus, M.) The colourless 

 Distiffma. Body smaller than the preceding, proteus-like, 

 sometimes greatly distended, at others constricted, blunted 

 at both extremities ; eyes distinct. Group 81 represents 

 these creatures highly magnified. Found amongst conferva. 

 Length l-580th to l-400th. 



142. DISTIGMA viride. The green Distigma. Body 

 the least of the genus, proteus-like, sometimes greatly 

 distended, at others constricted ; filled with green granules ; 

 eyes distinct. Length riot exceeding l-570th. 



143. DISTIGMA planaria. The eel-shaped Distigma. 

 Body small, linear, proteus-like, but less distended or con- 

 stricted than the preceding, pointed at both extremities ; 

 colourless ; eyes distinct. Found by Ehrenberg amongst 

 conferva in water of the Nile. Length 1 -240th. 



