126 Rhodora [AvavsT 
Navicula amphirhyncus Ehrenb., but exhibited an oblique stauros. 
This might appropriately have been called obliqua, but as Gregory 
had appropriated this name for an entirely different and much smaller 
form, I named it S. nova britannica, and it was so published in Dr. 
Bigelow’s Observer. Gregory’s form was not strictly a Stauroneis; 
it Was a very small stauroneiform Scoliopleura, and its stauros was 
not oblique. This New Britain Stawroneis is the most rare species 
of which I have any knowledge; Mr. Stone’s original gathering con- 
tained some hundreds, perhaps thousands of specimens, but on sub- 
sequent investigation no more could be found; they were probably 
confined to a very thin stratum of the deposit which was not identified, 
and further exploration is difficult if not impossible as the ground is 
covered with buildings. . 
Connecticut waters also are rich in living diatoms, and recent 
deposits abound. Nearly every lake and pond has its bottom covered 
with a soft ooze, which is filled with diatoms and is often two or more 
feet in thickness. The margins of rivers, ditches in the marshes, and 
the bottoms of small streams and rills in springy mountain pastures, 
furnish them in abundance. A small stream in a marshy pasture on 
Fall Mountain in Bristol has an abundant colony of the large variety 
of Stauroneis acuta W. Sm., many times larger than the type of Wm. 
Smith. I have a slide sent me by Prof. H. L. Smith which he assured 
me was part of the original gathering from which 'T'uffen West made 
the drawing of S. acuta for Smith's British Diatomaceae; this is the 
same as the Pleurotaenium acutum of other authors, and is distinctly 
different from the large Bristol Stawroneis. In the colony I find 
another Sfauroneis which is quite remarkable; it is longer and more 
cylindrical than the other species, has a broad stauros and rounded 
ends with a large saucer-shaped pseudonodule near each end of the 
upper valve but none on the lower valve. Next to the New Britain 
Stauroneis this is the most rare of all our species of diatoms. They 
may be gathered in hundreds from a space of about thirty feet on this 
brook, but they are so much outnumbered by other species with them 
that it is difficult to find them after they are collected; I have found 
a single specimen in each of three widely separated ponds in Bristol, 
but they are known nowhere else. Dr. Ward named this species 
Stauroneis Terryi. ln another small stream on Fall Mountain, Mr. 
W. C. Richards found a colony of Navicula elliptica Kütz., notable 
for abundance and size of individuals. 
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