8 Transactions. — Zoohf/i/. 



(b), with globular segments. Colour green. Transverse and 

 longitudinal furrows, and belt of cilia, normal of the genus. 

 Flagellum long, slender. 



Length, -j-^ inch — 17 ft. 



Hutt Valley, W. M. Maskell. 



Allied to G. pnlvisculus, Ehrenb. 



Gymnod'mium fuscum, Ehrenb. Masterton. 



Class II. CILIATA. 

 Order. Holotricha. 



Genus Nassula. 



Nassula ambigua, Stein., var. tumida, var. nov. Plate I., 

 fig 10. 



Animalcules free-swimming, flexible, evenly elliptical, cuticle 

 covered with fine cilia. Colour yellow ; the ingested food-parti- 

 cles green or brown. Pharynx very large, tumid, dilated at 

 the middle, slightly inclined, situated near the anterior edge ; 

 pharyngeal rods conspicuous. Contractile vesicle single, sub- 

 central, situated somewhat posteriorly. 



Length, 75^0 mcn = 105 /x. 



Hutt Valley, W. M. Maskell. 



This form is rounder and more regular than the European 

 species, and the pharynx is larger aud more tumid in the 

 middle. 



Genus Choenia. 



Choenia crassa, sp. nov. Plate I., fig. 11, a, b. 



Animalcules free-swimming. Colour brownish-white ; not 

 highly extensile but plastic and flexible ; vermiform, tapering 

 slightly anteriorly, more so posteriorly ; cuticle finely ciliate. 

 Anterior margin a little dilated and rounded, the oral aperture 

 situated at the apex, followed by a narrow alimentary canal, 

 capable of great distension, as shown in fig. 11, b. Contractile 

 vesicles twelve or more, situated along one side. Adoral cilia 

 somewhat longer than the rest. 



Length variable, from fa inch = 833 f.i to fa inch = 625 fx. 



Wellington, Hutt Valley, Wainui, Karori, II'. M. Maskell. 



The European C. teres has a salt-water habitat, and is more 

 slender and much more elastic than this species. Trachelitis 

 striates, Dujardin, is apparently somewhat similar, but seems to 

 be nearly identical with C. teres. 



The distension of the oral aperture and canal, shown in 

 fig. 11, b, was observed on one occasion while the animalcule 

 was engaged in devouring another infusorian, Urocentrum turbo, 

 which is here represented as passing bead foremost into the 



