Fig. 4. Turbinellid Ex/i/a narymensi s (Beisel, 1991) from Narymskaja borehole 28-k, Western Sibe- ria, Russia, Maastrichtian. A. ZPAL Ga.10/47; At — A> lateral views, A> protoconch in lateral view,

A4 apical view. Mesozoic gastropods from Siberia and Timan absent or weakly developed. Peristome elongated with long siphonal canal. One columellar plait present.

Description. — The protoconch 1 is not preserved. The protoconch 2 has no ornament preserved. The teleoconch is ornamented by about nine spiral ribs on the visible part of whorl. The growth lines are opisthocyrtic.

Remarks. — The Siberian species differs from other species of Exilia by hav- ing the axial ribs weakly developed. Exilia sp.

(Fig. 5)

Material. — One juvenile shell from Krasnyj Agronom, borehole 28-k, West- ern Siberia, Russia, Gankin Fm, Maastrichtian.

Dimensions. — The shell (ZPAL Ga.10/48), consisting of about six teleo- conch whorls, is 9.10 mm high and 3.80 mm wide.

Description. — The shell is high spired with weakly rounded whorls. The protoconch is not preserved. The teleoconch is ornamented by weakly opisthocline strong axial ribs and numerous weaker spiral ribs. The peristome is not visible.

Remarks. — The shell is most similar to the shells of Exilia lincolnensis Weaver, 1916 from Eocene of Washington (USA) illustrated by Kantor et al. (2001). The latter species differs in more elongated shell shape. Fig. 5. Turbinellid Exilia sp. from Krasnyj Agronom, borehole 28-k, Western Siberia, Russia, Maastrichtian. A. ZPAL Ga.10/48; At lateral view, A> apex in lateral view, A3 details of teleoconch

ornamentation. Gen. et sp. indet.

(Fig. 6)

Material. — One juvenile shell from Narymskaja, borehole 28-k, Western Si- beria, Russia, Gankin Fm, Maastrichtian. 48

Andrzej Kaim and Alexander L. Beisel Fig. 6. Turbinellidae gen. et sp. indet. from Narymskaja borehole 28-k, Western Siberia, Russia, Maashichtian. A. ZPAL Ga. 10/47; A ~ lateral view, Az apex in lateral view, As apical view, A4 details

of teleoconch ornamentation.