This is a scanned in image from a previous
picture of the specimen. The specimen is tilted
on the slide and dificult to get a clear picture of,
this was the best picture.
Surirella guatimalensis Ehrenberg 1854, 33/6, fig. 7
These are images taken from a scanning electron microscope. The offer an excellent close up view of the detials of the frustule. Clockwise they show progressively higher magnification of the frustule where there is a wing gap.
The valve has heteropolar ends with a broad head pole and a more narrow foot pole. The wing projection is vague to invisible. The wing at the head pole is not continuous all the way around, rather it is interupted by a broad gap. The ribs are short and the greater part of the valve surface is flat, the wavy part is small and rib-like in appearance. The Frustule is finely striated with fine punctae that are uneven in appearance and form lingitudinal rows.
Surirella cardinalis Kitton 1868, p. 132, fig. 133
Novilla guatimalensis (Ehrenberg 1854) according to F. W. Mills 1934, p. 1245
Length is 100 to 240 micrometers (Huber-Pestalozzi 1942).
Width is 60 to 110 micrometers (Huber-Pestalozzi 1942).
Wing canal has 25 to 35 ribs in 10 micrometers (Huber-Pestalozzi 1942).