Reprint from Journal of National Cancer Institute (series). 118. Cytological studies on nature of cytoplasmic particulates in Cloudman S91 mouse melanoma, derived Algire S91A partially amelanotic melanoma, and Harding-Passey mouse melanoma [with list of references]; by M. W. Woods, H. G. DuBuy, Dean Burk and Marie L. Hesselbach.