Eduwndson — Crustacea from Palmyra and Fanning Islands 7 



to be the only representatives of the group. Both the outer shore and the 

 lagoon were found to be rich in invertebrate fauna, especially of the 

 echinoderm, molluscan and crustacean phyla and many species of each of 

 these were taken. This paper deals only with the crustaceans. 



The surface waters of the lagoon were found to be teeming with ento- 

 mostracan crustaceans, larvae of mollusks, crabs, and such like which no 

 doubt serve as food for the numerous fishes. Determination of the species 

 of the tow material collected has been made only in part and few forms 

 from that source are included in the Hst which follows. 



Although by no means an exhaustive one, and very limited in respect 

 to certain groups, the systematic record following may be considered fairly 

 representative of the crustacean fauna of atolls of the mid-Pacific region. 

 The data relative to the distribution of the species is sufficient to disclose 

 the very extensive range of many of the forms taken at Palmyra and Fan- 

 ning Islands. A similarity of the crustacean fauna of the Indian Ocean 

 to that of these two islands is obvious. It will also be noted that many 

 species are common to Fanning and Palmyra Islands and Hawaii. 



The Indo-Pacific crustacean fauna has clearly extended eastward in the 

 Pacific as far as the Marquesas and the Tuamotus and some species have 

 reached Easter Island. Its influence also includes the Hawaiian Group and 

 a few species .^have apparently reached the American coast and more that 

 of Japan, while a few other species, having even a wider distribution, are 

 included in the fauna of the warmer waters of the Atlantic as well as 

 that of the Indian and Pacific Oceans. It is also evident, so far as our 

 present knowledge goes, that Palmyra and Fanning islands mark the 

 northern distributional limit in the mid-Pacific region of certain Indo- 

 Pacific species. 



In addition to previous acknowledgments credit is due Drs. Mary J. 

 Rathbun and Waldo L. Schmitt of the United States National Museum 

 for services rendered in the identification of certain species included in this 

 paper. Rathbun also described two new species of crabs from Palmyra 

 Island. (See p. 38.) For the outline drawing of Fanning Island (fig. i) 

 and for three photographs Plate \,A,B. and Plate 11,5 I am endebted to 

 Mr. Clarence Brown, a civil engineer of Honolulu who completed a topo- 

 graphical survey of the atoll in 19 19. 



The systematic report is based upon approximately 800 specimens col- 

 lected at Palmyra Island in 1913 by C. Montague Cooke, Jr. and Joseph 

 F. Rock ; 190 specimens taken by Messrs. Lorrin Thurston and David 

 Thaanum at the same island in 1922, and 800 specimens collected at Fan- 

 ning Island by Stanley C. Ball and me in 1922. 



