Tip pointed, siphonal
capsule asymmetrical, outer arm larger and inner arm smaller.
All whole whelks were weighed for total weight, measured for SL (SL; spire apex to the edge of siphonal
canal), and shell width [SW; maximum straightline distance measured across the shell perpendicular to shells length (coiling) axis] to nearest 1 mm (Fig.
gigas larvae (28 days old), showing: A) Organs used to evaluate larval development; B) Areas used to measure siphonal
length (LS) and to perform Calcium measurements by EDX analysis.
Shell length (apex to tip of siphonal
canal) was measured with digital calipers (MaiCal 16 EWR; Mahr GmbH, Gottingen, Germany).
Primary ribs bear strong spiny umbilical tubercles, less marked inner ventrolateral tubercles and well marked clavate outer ventrolateral and siphonal
canal short and broad, approximately half of aperture width, left edge truncate, right edge wanting, as continuation of outer lip; left edge marked by two strong spiral folds, superior fold smooth, with sharp edge, inferior fold broad, with several arched, strong growth scales (Fig.
They were present at quite a high density (four to five per square metre) projecting by as much as 10 mm above the cobble surface "with bottle-green siphonal
orifices sampling the stream water.
The only way of visually separating the shells of the two species is the presence of a patch of dark coloration near the siphonal
canal of C.
Unionids move vertically and horizontally in the substrate, open and close their valves and may expel strong siphonal
dark basic colony color, bright yellow around siphonal
The proboscis slips out the siphonal
canal, unrolling, the barbed teeth spring forward.
Cages either excluded whelks or enclosed two or six whelks (15-22 mm in length from apex to siphonal
canal), corresponding to densities of 0, 50, and 150 whelks/[m.