A poor fourth-quarter showing marred an otherwise steady financial performance in 1987 for Versar Inc. of Springfield. The environmental consulting firm had net income of $749,000 (24 cents a share) on sales of $38.3 million for the fiscal year that ended June 30, compared with profits of $783,000 (32 cents) on sales of $28.2 million for fiscal year 1986. In the fourth quarter of this year, however, the firm's profits slipped to $63,000 (1 cent) on revenue of $12.2 million, compared with $475,000 (20 cents) on sales of $8.3 million for the same period last year.

Company officials blamed the poor fourth-quarter showing on staff limitations in some operations and lower than expected sales in the environmental business division.

Since going public one year ago, the firm has acquired two companies, undertaken a third acquisition, developed several regional offices and expanded its laboratory capacity.

Webster Clothes Inc. of Baltimore announced earnings of $102,000 (3 cents a share) on revenue of $23.1 million for the first six months of 1987 that ended Aug. 1, compared with profits of $440,000 (14 cents) on revenue of $19.3 million for the first six months of last year.

In the second quarter of this year, the firm recorded net income of $148,000 (5 cents) on revenue of 12.7 million, compared with profits of $371,000 (11 cents) on revenue of $10.8 million for the same period last year.

Samuel M. Feldman, president and chairman of Webster, expressed disappointment in the results, but said sales performance was stronger in July and August. He also noted that the third and fourth quarters are traditionally stronger periods for the firm.

Webster Clothes also announced the acquisition of the West Coast clothing retailer Z&Z Fashions Ltd.

The firm will buy 52 percent of Z&Z's shares from major shareholders, providing it can acquire an additional 15 percent of Z&Z stock from other shareholders. Under the agreement, Webster also will commence a cash tender offer for the shares of Z&Z common stock not covered by the purchase agreement at $2.75 a share.

The total price of the acquisition is expected to be about $2.4 million.

Z&Z has an annual sales volume of about $10 million from 19 retail stores in San Diego, Los Angeles, San Francisco and Las Vegas. With the acquisition and a 16-store expansion this year, Webster will be operating 128 stores by the fourth quarter of this year, company officials said.