as objects for paleobiogeographic study.
(2006) recognized "internal germination opercula
" in some of the genera, e.g., Harpephyllum and Spondias.
Issues with the use of opercula
have largely focused on the clarity and readability of surface rings.
The results from that workshop indicated that, with increased experience by the staff, the use of sectioned otoliths from tautog may yield age estimates of higher precision than the use of opercula
. After that workshop, sectioned otoliths have been used as a supplementary method for age determination (ASMFC (2)).
movement, surfacing and gulping of air were observed.
Snails previously reported as surviving fish gut passage were members of the subclass Prosobranchia, like valve snails, and were thus equipped with opercula
(Haynes et al., 1985; Aarnio and Bonsdorff, 1997).
Most of the archaeological materials that were removed from the site were the smaller, more fragmented pieces such as Turban (Turbo sp.) shell and opercula
, fragments of crustacean and small bivalves (Table 1).
Live and dead adult and subadult Bellamya japonica with their opercula
missing and with part or most of their large, muscular foot bitten off by muskrats have been found singly or in clusters ("middens") of up to 64 individuals on dozens of occasions from September 1993 to present in shallow waters (0-0.5 m deep) along the shoreline of Salt Fork Lake.
The dyslexic participants did, however, have type II-III opercula
and extra Heschl's gyri (Figure 7).
This could be accomplished actively with radical changes in behavior (e.g., swimming backwards with opercula
The occurrence of calcareous deposits in rissooidean opercula
is sporadic, even within families and genera.