164 
Notes . 
Table , illustrating comparative constitution of the Plankton of the Trent , 
Thames and Cam during the month of August 1 . 
Trent. 
25, viii. 
t= i 4 °C. 
Thames. 
19, viii. 
t - 18 0 C. 
Cam. 
29, viii. 
t = 1 6° C. 
Scenedesmus quadricauda (Turp.), Brdb 
rc. 
r. 
— 
„ acutus , Meyen, var, obliquus, Rabh. . . 
rr. 
— 
vr. 
Pediastrum Boryanum (Turp.), Men. . . , . . 
r. 
c. 
r. 
,, pertusum , Ktz 
vr. 
r. 
— 
Chlamydomonas spec 
vr. 
vr. 
— 
Eudorina elegans. , Ehrb. 
— 
c. 
_ 
Pandorina morum, Ehrb. 
vr. 2 
r. 
— 
Volvox globator , L 
vr. 2 
— 
— 
Coelastrum microporum, Naeg. 
vr. 2 
— 
— 
Closterium acerosum (Schrank), Ehrb 
vr. 
— 
— 
,, moniliferum , Ehrb 
rc. 
c. 
rc. 
„ lunula (Mull.), Nitzsch ...... 
vr. 
— 
— 
Cosmarium margaritiferum , Men 
— 
rc. 
rc. 
,, granatum , Breb 
vr. 
-r 
— 
Melosira arenaria, Moore 3 , . . 
— 
c. 
r. 
„ varians , Ag. ........... 
rc. 
VC. 
c. 
Cyclotella operculata (Ag.), Ktz 
rc. 
rc. 4 
__ 
Campylodiscus noricus, Ehrb 
vr. 
r. 
vr. 
Surirella splendida (Ehrb.), Ktz 
vr. 
r. 
— 
„ ovata , Ktz 
vr. 
— 
— 
Cymatopleura Solea (Brdb.), Sm. ....... 
rr. 
rc. 
— 
,, elliptica , Br^b. 
vr. 
rc. 5 
— 
Himantidium faba, Ehrb 
— 
r. 
— 
Cymbella gastroides , Ktz 
rr. 
c. 
rc. 
A mphora ovalis , Ktz 
— 
rc. 
— 
Cocconeis Placentula, Ehrb. 
r. 
rc. 
rc. 
Fragilaria virescens , Ralfs 
rc. 
vc. 
rc. 
,, mutabilis (Sm.), Grun 
— 
rc. 
— 
Synedra Acus, Ktz 
rc. 
r. 
— 
„ Ulna , Ehrb 
rc. 
rc. 
c. 
Nitzschia sigmoidea (Nitzsch), Sm 
rr. 5 
rc. 
— 
Navicula gracilis, Ehrb 
— 
rc. 
— 
,, exilis , Grun.? 
— 
— 
c. 
„ lanceolata , Sm 
_ 
vc. 
Pinnularia viridis (Ehrb.), Rabh . 
— 
r. 
— 
Pleurosigma attenuatum (Ktz.), Sm 
-r 
c. 
r. 
Tabellaria fenestrata, Ktz 
— 
rc. 
rr. 
Bacillaria paradoxa, Gmel 
vr. 2 
— 
— 
Merismopedia glaucum (Ehrb.), Naeg 
vr. 
— 
— 
Microcystis spec 
r. 
-r 
— 
Oscillaria spec 
r. 
— 
r. 
Euglena viridis , Ehrb 
vr. 
rc. 
— 
Phacus pleuronectes, Nitzsch 
vr. 
— 
— 
Synura Volvox, Ehrb 
— 
r. 
_ 
Ceratium hirundinella, O. F. M. . . . , . . . 
vr. 
— 
— 
1 vc. = very common ; c. = cpmmon ; rc = rather common ; rr. = rather rare ; r. = rare ; vr. = 
very rare. 
2 Only one individual seen. 
3 I take this opportunity of correcting an incorrect determination. The species described as 
Melosira moniliformis , A g., in the former papers is really M. arenaria, Moore. 
4 On looking through old preparations of Thames Plankton from Maidenhead I found this 
species present in some amount. 
5 Occasionally with epiphytic individuals of Amphora minutissima . 
