12 Frot. 
PROTOZOA. 
Pseudodifflugia gracilis?^ (8) p. 198, pi. xxxiii. figs, 18-28, N. America. 
P. amphora^ 1. c. p. 201, new variety described, Wyoming. 
Cyphoderia ampulla, (8) p. 202, pi. xxxiv. figs. 1-16. 
Campascus cornutus, (8) p. 205, pi. xxxiv. figs. 17-24. 
Euglypha (8). The species graduate into each other. Five species 
from N. America, viz., E. alveolata, p. 207, pi. xxxv. figs. 1-18, conjuga- 
tion very fully observed ; ciliata, p. 214, pi. xxxv. figs. 19 & 20, pis. xxxvi. 
& xxxvii. figs, 30 & 31 ; cristata, p. 218, pi. xxxvii. figs. 1-4; mucronata, 
p. 219, pi. xxxvii. figs. 11-14 ; brachiata, p. 220, pi. xxxvii. figs. 6-10. 
Euglypha alveolata, figured from Australia, Q. J. Micr. Soc. Victoria, 
i. p. 17, pi. i. figs. 1-16, 0. M. Maplestone. 
Euglypha spinosa, (8) p. 221, pi. xxxviii., = Placocista, g. n. 
Assulina seminulum, (8) p. 225, pi. xxxvii. figs. 15-27. 
Trinenia enchelys, (8) p. 226, pi. xxxix. Very variable in form and 
size, including many species of Ehrenberg. 
Sphenoderia, (8). Two species from N. America, viz., lenta, p. 229, 
pi. xxxiv. figs. 25-41, and a new specie.s. 
Difflugia (8). 10 species in N. America, viz. : D. glohulosa, p. 96, pi. xv. 
figs. 25-31, pi. xvi. figs. 1-24, shows transitions io pyr if or mis, which, 1. c. 
p. 98, pis. X. xi. & xii. figs. 32 & 33, pi. xvi. fig. 38, pi. xix. figs. 24-26, has 
many varieties ; D. urceolata, p. 106, pis. xiv, & xvi. figs. 32-34, pi. xix. 
figs. 28 & 29, merges into acuminata, p. 109, pi. xiii. ; D. cratera ?, p. 108, 
pi. xii. figs. 19-21, pi. xvi. fig. 35, the tests may be merely those of a 
Tintinnus : D. lobostoma, p. 112, pi. xv. figs. 1-24, pi. xvi. figs. 25-29, 
sometimes three individuals conjugate ; D. arcula, sp. n., or var., vide 
infra ; D. corona, p. 118, pi. xvii., merges into lobostoma', D. constricta, 
p. 120, pi. xviii. ; D. spiralis, p. 124, pi. xix. figs. 1-23, observed to con- 
jugate in various numbers at once. 
Difflugia sphagni, Leidy, = type of Heleopera, g. n., Leidy (8), vide 
infra. 
Difflugia proteiformis, Ehrb., from the bottom of the Lake of Geneva, 
is more transparent than marsh specimens ; it has the power of pro- 
ducing bubbles of gas internally, by which it mounts to the surface. G. 
DU Plessis, Bull. Soc. Vaud. (2) xvi. p. 167. 
Hyalosphenia (8), 4 species in N. America, viz. ; cuneata, p. 129, pi. xx. 
figs. 1-10 ; papilio, p. 131, pi. xxi., which always contains chlorophyll, 
and is very uniform in its characters ; tincta, sp. n. ; elegans, p. 140, 
pi. XX. figs. 19-29. 
Quadrula symmetrica, (8) p. 142, pi. xxiv. figs. 20-25, from N. America. 
Nebela (8). 7 species from N. America, viz. ; N. collaris, p. 145, pis. xxii. 
& xxiii. figs. 1-7, pi. xxiv. figs. 11 & 12 ; N. fabellum, p. 152, pi. xxiii. 
figs. 8-19 ; N. carinata, p. 154, pi. xxiv. figs. 1-10 ; N. hippocrepis, p. 156, 
pi. XXV. figs. 9-14 ; N. ansata, p. 158, pi. xxv. figs. 1-8 ; N. barbata, 
p. 159, pi. xxiv. figs. 14' 17 ; N. caudata, p. 160, pi. xxvi. figs, 21-24. 
Hyalodiscus rubicundus ?, (8) p. 94, pi. xlv. figs. 17 & 18, N. America. 
Echinopyxis aculeata, Ehrb., Amer. Quart. Micr. Journ. i. p. 83, pi. viii. 
fig. 3, America. 
Arcella, (8) p. 156. Generally has two nuclei. The species doubtfully 
distinct. Gas-bubbles sometimes produced within the protoplasm. Five 
