DISTRIBUTION OF THE HYDROIDS IN THE 



COLLECTIONS OF THE 



ALLAN HANCOCK EXPEDITIONS 



C. McLean Fraser 



Three papers on the Hancock hydroids have appeared, one on those 

 collected in 1934, one on those in 1936 and 1937, and one on those in 

 1932, 1933, 1935, and 1938. In the first paper some attention was given 

 to general distribution; in the other two little consideration was given 

 to it, apart from the distribution records. Since several species are re- 

 corded in these two papers that were not in the first one, it may be an 

 opportune time to review the situation to date, in the area covered by 

 the expeditions, viz., the east coast of the Pacific from the northern 

 boundary of Mexico to the southern boundary of Peru, and the Oceanic 

 islands related to this area. 



Before 1932, when the first Hancock hydroids were collected, very 

 little was known of the hydroid fauna of this area. In 1891, the United 

 States Fish Commission Steamer Albatross did some dredging off the 

 Mexican and Central American coasts and S. F. Clarke recorded ten 

 species from the material, all within one hundred miles of Panama, 

 except one from the coast of Nicaragua. In 1904 and 1905, the Albatross 

 did some dredging at widely distant stations in this general area and 

 from the material Clarke recorded twelve species. Two species were 

 common to the two collections, so there were 20 recorded in all. These 

 were: 



Eudendrium sp. 



Pennaria pacifica Clarke 



Campanularia obliqua Clarke .y^^nV^'^ 



Obelia castellata Clarke ' ""'' 



Obelia striata Clarke 



Obelia sp. 



Campanulina denticulata Clarke 



Halecium argenteum Clarke 



Halecium gracile Bale 



Acryptolaria conferta (Allman) 



Acryptolaria pulchella (Allman) 



Lafoea convallaria Allman 



Lafoea gracillima (Alder) 



Lictorella geniculata Clarke 



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