180 Rhodora (Остовев 
is Downs’ Pond, a large part of which is a cove setting back from 
the river, in which the mud is three or four feet deep, all very rich in 
diatoms, including abundance of the species in question, which is 
abundant also in Thompson’s Pond, on the headwaters of a small 
brook flowing into Downs’ Pond, and Allen’s Pond in Stafford district, 
near the northeast corner of Bristol, on the headwaters of a small 
stream, and Beattie’s Pond, at Leete’s Island. At this last station are 
also other rare species, including Navicula peripunctata Brun, Pleuro- 
sigma simile Grun., and the very rare P. subsalinum Per. Outside 
these ponds above noted I have never found more than an occa- 
sional specimen of S. Terryi in all the hundreds of gatherings by 
myself and others from streams, ponds, lakes and rivers all over the 
country. Of the seven ponds in which this species is found, four 
are on the headwaters of streams many miles apart, but all in Con- 
necticut, while the others are on the Pequaback River. 
The following lists from the third and fourth fascicles of the Dia- 
tomées du monde entier are from my material and are interesting 
as being the latest and most authoritative determinations; many 
species here given were not in my list! and some of them have never 
before been credited to North America. In spelling, abbreviations 
and italics, the original is followed; the explanation as there given is 
— "Nota. Le nom des espéces prédominantes sont imprimés en 
caractère gras; les rares en italique et les autres en caractère courant." 
The Fall Mountain gathering was from a small brook flowing 
from a mountain spring; Bunnell’s Pond is the highest in a series 
of ponds on a stream flowing from South Mountain reservoir. 
Хо. 78. Ice Ponp, New Ввітлім, (Connecticut, U. S. A.). 
Achnanthes coarctata Grun. Encyonema lunatum Grun. 
Amphora libyea Ehr. Epithemia argus у. amphicephala 
ovalis Ktz. Grun. 
pediculus Ehr. gibba Ktz. 
Cymbella amphicephala Хаер. v. ventricosa Кёл. · 
Ehrenbergii Кіл. zebra v. proboscida Grun. 
gastroides Ktz. Eunotia diodon Eh. fa. minor. 
naviculaeformis Auers. impressa Grun. 
1 RHODORA, Vol. IX, р. 125. 
