Lab-supplies developer

Ventana Medical Systems

(VMSI)

has acquired 22 million shares of Australian medical-technology company

Vision Systems

.

The acquisition represents 10.2% of Vision Systems' shares, priced at A$2.85 each. Tucson, Ariz.-based Ventana says it filed a substantial shareholder notice with Vision Systems, as required under the Australian Corporations Act.

Ventana's shares fell 31 cents, or 0.8%, to $40.74.

Earlier this week,

Cytyc

( CYTC), another bidder for Vision Systems,

trumped Ventana's

previous offer.

Vision Systems, a maker of lab machines, has also discussed its sale with Washington's

Danaher

(DHR) - Get Report

.