Guam, Toguon Bay, 8m; 27 May 1993 (C.27) [the average size of the animals we have measured is a little over 4mm -- the largest 5.5mm. we don't look for largest and mallest so there are probably larger forms around.] PHOTO: C. Carlson & P.J.Hoff.
Here is a photo of some examples from a breeding population which gives some idea of the variation that may occur. A common form not shown has a single red line. Ventomnestia villica may be the same as V. bizona (A. Adams, 1850).
Ventomnestia has a fairly heavy shell, gizzard plates with 6 to 7 heavy ridges covered with rods. The radula formula for V. villica is 2.1.2.
One characteristic of the haminoeids is the absorption of all but the outer 1 1/2 whorls of the shell. This is also true of V. villica, except that the periostracum has been retained so that the liver remains coiled.
Earlier studies based upon shell alone had Ventomnestia as a cylichnid or retusid form. It is a good example of the need for wet material (e.g. living/preserved from living specimens) in the study of the bubble shells.
C. Carlson & P.J.Hoff.
• Gould, A.A. (1859). Descriptions of shells collected in the North Pacific Exploring Expedition under Captains Ringgold and Rodgers. Proc. Boston Soc. Nat. Hist., 7: 40-166
Carlson, C. & Hoff, P.J., 2000 (February 3) Ventomnestia villica (Gould, 1859). [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/factsheet/ventvill