non-uniform trend in the sky distribution of EROs and clustering in southern part of MS $0451.6-0305$, while near the image center in MS $0440.5+0204$.

Counterparts of SCUBA Sources
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### SCUBA sources in MS $0451.6-0305$

Two sub-mm sources, SMM J $04542-0301$ and SMM J $04541-0302$, were detected in a survey of massive clusters using SCUBA by Chapman et al. (2002a).

SMM J $04542-0301$ is located at 25from the cluster center, and elongated to about 1long, which is suggested to be a blend of multiple SCUBA sources (Chapman et al. 2002a). Its total flux at 850 $\mu$m is 19.1 mJy, and the magnification factor by cluster lensing is estimated to be 4.5. There is a constraint of the redshift for this source, as at $z \geq$ 2.3 using the ‘sub-mm’ vs ‘cm’ spectral index (Yun, Carilli 2002). We found 7 EROs and 3 optically bright ($R_{\rm{c}} \sim 23--24$) very red objects($R_{\rm{c}}-K' \sim$ 5) around this sub-mm source, as shown in figure 4. The photometric parameters for these objects are summarized in table 1. “A1” and “A4” are very faint, even in a very deep (10400 s exposure) F702W image, and “A2” and “A3” are not visible in it. We plot $R_{\rm{c}}-K'$ 