Maskell. — On Freshwater Infusoria. 15 



eacli side of the pharynx. Nucleus round, placed close to the 

 posterior extremity. 



Length r ± T) inch = 131 jx. 



Wellington, W. M. Maskell. 



Longer and narrower than P. vorticella, Stein, and differing 

 also in the positions of the nucleus and the contractile vesicles. 



Genus ^Igyria. 

 Myyria astyla, sp. nov. Plate IV., fig. 24. 



Animalcules free- swimming, persistent in shape ; seeming as 

 if bivalved ; colour brownish ; ventral surface concave, edge 

 furnished with long cilia ; dorsal surface convex, not ciliated. 

 Valves narrow, slightly widened posteriorly. Contractile vesicles 

 two ; nucleus not observed. No anal style. No pigment-spot. 



Length, F ^j inch = 70 ix ; average width of valve, j^q mcu 

 = 17-5 fi. 



Pahautanui, W. M. Maskell. 



Most of the species of this genus inhabit salt water. 2Egyria 

 fiuviatilis, Stein, the only freshwater form reported from Europe, 

 appears to be conspicuously ribbed. The presence of an anterior 

 pigment-spot is noticed in one European species, Mgyria oliva, 

 C. and L. 



Mgyria distyla, sp. nov. Plate IV., fig. 25. 



Animalcules free-swimming, as if bi-valved, the valves a 

 good deal broader than in the last species ; colour brownish- 

 yellow ; ventral surface concave, edge furnished with long cilia. 

 A pigment- spot noticeable at the anterior end. At the posterior 

 extremity two short, sharply triangular styles. Contractile 

 vesicle single, sub-central. 



Length, ^^ inch = 70 /x ; average width of valve, yi^ inch 

 = 35 jx. 



Hutt Valley, W. F. Barraud. 



In general contour this resembles JE. oliva, an European 

 saltwater species, but differs in the double anal styles and the 

 single contractile vesicle. 



Genus Thurophora, gen. nov. (Gr. 6vpa, a door). 



Animalcules free-swimming, encuirassed ; oral region partly 

 closed by a vibratile, apparently hinged, membrane. 



This genus is placed here in the order Hypotricha, because, 

 although in the only species observed there are some short cilia 

 on the dorsal surface, these differ greatly from the long ventral 

 cilia which alone appear to have any locomotive character. The 

 animalcules are, however, sufficiently anomalous to render it 

 somewhat difficult to know where they should strictly be placed. 

 The hinged membrane differs from the extensile pouch of 



