pally on three lines of evidence: comparative mor- 

 phology, fossil records, and larval development 

 (Stevcic 1971). Based primarily on comparative 

 morphology of adult crabs and sparse fossil re- 

 cords, the family Dromiidae has usually been con- 

 sidered primative but true brachyurans (Balss 

 and Grunner 1961; Burkenroad 1963; Glaessner 

 1969; Hartnoll 1975; Warner 1977). 



In contrast to these findings, the larval de- 

 velopment of dromiids is, in many aspects, typi- 

 cally anomuran. Gurney (1924) found all larvae of 

 Dromia to be "definitely Anomuran." Brachyuran 

 and anomuran larvae have since been well charac- 

 terized in several comprehensive studies (Gurney 

 1942; Pike and Williamson 1960a; Williamson 

 1974); the findings of Gurney (1924) have been 

 consistently substantiated. The megalopa is not so 

 easily characterized and appears to more closely 

 resemble its parents than both postlarval anomu- 

 rans and nondromiid brachyurans (Wear 1977). A 

 detailed account of the classification of the 

 Brachyura and a proposed new system has re- 

 cently been published by Guinot (1978). 



The Brachyura are characterized not only by the 

 advanced organizational level of adults but also by 

 a consistant larval form. The evolutionary path 

 should include "brachyurization" to both a crab 

 body (Stevcic 1971) and a "brachygnath zoea" 

 (Williamson 1974). A key to better understanding 

 the dromiids is to find larval types which appear to 

 lead toward a brachygnath form. If, like the 

 Dromiidae, the Dynomenidae and Homolo- 

 dromidae are found to have larvae showing no 

 tendency to develop brachygnath features, the 

 Dromiacea (Guinot 1978) may have progressed 

 toward a crablike form independent of lines lead- 

 ing toward the true brachyurans. 



The combination of adult and larval charac- 

 teristics exhibited by the Dromiidae has not been 

 satisfactorily explained. In view of obvious con- 

 tradictions and the relative importance of adult 

 morphology in decapod classification, removal of 

 the Dromiidae from the Brachyura based solely on 

 known larval features (Gurney 1924, 1942; 

 Kircher 1970; Williamson 1974) is not warranted. 

 Placement of the Dromiidae within the 

 Brachyura, is by no means "of little doubt" as 

 claimed by Warner (1977) but represents more a 

 matter of convenience (Guinot 1978); their posi- 

 tion is tenuous at best. Hopefully additional mate- 

 rial (larval, morphological, or fossil) will lead to a 

 comprehensive account of the Dromiidae and re- 

 lated families. 



FISHERY BULLETIN VOL. 77, NO- 4 



ACKNOWLEDGMENTS 



This study was initiated by the authors while at 

 the University of South Carolina. The authors ex- 

 press their appreciation to the Belle W. Baruch 

 Institute for support. Aid for completion of this 

 project was provided by the EPA Environmental 

 Research Laboratory at Narragansett, R.I., par- 

 ticularly through the cooperation of Don C. Miller 

 and Donald K. Phelps. Akella N. Sastry, Graduate 

 School of Oceanography, University of Rhode Is- 

 land, generously allowed use of his microscope. We 

 would also like to thank Daniele Guinot, Richard 

 G. Hartnoll, Anthony L. Rice, and Zdravko Stevcic 

 for providing publications and useful information. 



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1961. Decapoda. XI. Stammesgeschichte. In Dr. H. G. 

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Burkenroad, M. D. 



1963. The evolution of the Eucarida, (Crustacea, 

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1893. Svillupo dei Dromidei. Atti. Accad. Sci. Fis. Nat,, 

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862 



