THE LARVAL DEVELOPMENT OF NORTHERN CALIFORNIA PORCELLANIDAE (DECAPODA, ANOMURA). I. PACHYCHELES PUBESCENS HOLMES IN COMPARISON TO PACHYCHELES RUDIS STIMPSON

¹ Pacific Marine Station, University of the Pacific, Dillon Beach, California 94929

Two species of Pachycheles (Decapoda, Porcellanidae) occur along the northern California coast: P. pubescens and P. rudis. The zoeae of the two species are very similar. At hatching they differ only in the setation of the first maxilliped, however they diverge later in development. The setation of the first maxilliped appears to be the most variable feature of species of this genus so far described. Chromatophore distribution, number of telson spines with hooks at the tip, and the absence of setules on the inner margin of the endopodites of the maxillipeds may prove to be important in differentiating Pachycheles from other Porcellanidae, particularly from the genus Petrolisthes.