


x891.] : Rocky Mountain Rhizopods. 1071 
I give now the list of the species I collected in various bogs or 
swampy grounds in the neighborhood of Caribou, and at a height 
varying from 10,000 to 10,500 feet. The animals were mostly 
found among mosses and sphagnum, whose presence at that 
altitude is itself remarkable. 
Ameba limax Dujardin, Amæba verrucosa Ehrenberg-Leidy, 
Diflugia pyriformis Perty, Difflugia arcula Leidy, Difflugia 
lucida Penard, Diflugia fallax Penard, Diflugia bacillifera Penard, 
Diflugia constricta Ehrenberg, Centropyxis aculeata Stein, Arcella 
vulgaris Ehrenberg, Arcella vulgaris var. angulosa Leidy, Arcella 
discoides Ehrenberg, Arcella microstoma Penard, Quadrula sym- 
metrica Schulze, Lecquereusia jurassica Schlumberger, Nedela 
collaris Leigy, Nedela longicollis Penard, Nebela tubulosa Penard, 
Nedela dentistoma Penard, Heleopera rosea Penard, Assulina minor 
Penard, Pseudochlamys patella Claparède and Lachmann, Crypto- 
diffugia oviformis Penard, Cyphoderia margaritacea Schlumber- 
ger, Euglypha alveolata Dujardin, Euglypha ciliata Leidy, Eugly- 
pha cristata Leidy, Euglypha compressa Carter, Euglypha levis 
Perty, Sphenoderta dentata Penard, Trinema lineare Penard; 
Trinema enchelys Leidy, Trinema enchelys var. galeatum Penard, 
Trinema complanatum Penard, Corythion dubium Taranck, Cory- 
thion pulchellum Penard. 
All these species, which did not differ in any particular from 
those which have been described from Europe, India, Australia, 
or from various parts of the United States, were generally found 
represented by very numerous individuals. Yet sometimes a 
very few were present in a given locality, or again some given 
species, entirely absent. from one place, was abundant in another 
and very near one. 
But there are a few of diese species on which I should like to 
write at some length: 
Difflugia pyrifermis Perty—This species is extremely variable ; 
or rather, if I may be allowed to express a personal opinion, 
should be and will be one day decomposed into a large number 
of distinct specific forms, some of which again will show an unde- 
niable tendency towards a great variability. In fact, my obser- 
vations, which have been protracted for several years and made on 

