fact, Cressey and Lachner (1970, loc. cit.) observed that remoras' stomachs usually did not contain copepod species which normally infested sharks' fins. Furthermore, clustering might also assist hydrodynamically in copepod attachment. As water passes over the cluster, the posterior of each individual should transfer a downward force to the underlying cephalothorax of the next posterior copepod. Through such a mechanism, the application of a copepod's attachment structures to its host might be facilitated. The clustering of P. satyrus females at a specific site may be a favorable reproductive trait considering the relatively small number of males present. How this interesting attachment scheme is initiated remains a mystery. I thank Mr. J. G. Casey for arranging my participation on the R/V Wieczno Cruise 7803, Mr. A. Lintala for taking the in situ photograph, and Dr. L. R. Penner for laboratory facilities used while studying copepods.