PART 1 GARTH : PACIFIC OXYRHYNCHA 227 



Genus EPIALTUS Milne Edwards 



Epialtus Milne Edwards, 1834, p. 344 (part). Rathbun, 1925, p. 144 



(part). 

 Epialtus (Epialtus) A. Milne Edwards, 1878, p. 138 (part: not E. 

 marginatus) . Miers, 1879c, p. 650. 



Type: Epialtus bituberculatus Milne Edwards, 1834, by subsequent 

 designation of Miers (1879c, p. 650). 



Description: Carapace broad, subpentagonal or oblong, almost 

 smooth, with two lateral, more or less laminate projections, sometimes 

 very largely developed. Rostrum broad, triangular or oblong, entire or 

 bilobed at tip. Eyes small. Preorbital tooth either present or absent; 

 postorbital small, minute, or wanting. Basal article of antenna triangular; 

 movable part concealed beneath rostrum. Chelipeds of male strong; 

 fingers either gaping or in contact; tips excavate or spoon-shaped. Am- 

 bulatory legs subcylindrical, diminishing successively in length from first 

 to fourth ; propodites sometimes with an inferior tooth or bunch of setae ; 

 dactyli with two rows of spinules beneath. Small species. (Rathbun) 



Abdomen of male with six segments, of female with five segments. 



The genus Epialtus as defined by Rathbun ( 1925, p. 144) represented 

 an advance over the previous arrangements of A. Milne Edwards and 

 of Miers in that it removed from the genus those American species hav- 

 ing seven free abdominal segments in both sexes and placed them either 

 in Taliepus or in Pugettia. In conformity with the general system 

 proposed for the Oxyrhyncha by Balss (1929, p. 2), in which the 

 number of free abdominal somites becomes a character useful in grouping 

 genera into larger categories, it has been found necessary to further 

 restrict the genus Epialtus to those species which, like the type, E. 

 bituberculatus, possess six free segments in the male and five in the 

 female. A separate genus, Epialtoides, has been erected to receive those 

 species previously referred to Epialtus (with the exception of E. 

 peruvianus, which has been transferred to Eupleurodon) in which the 

 number of free abdominal somites in the male is further reduced to five. 

 Epialtoides, therefore, stands in relation to the restricted genus Epialtus 

 as does Acanthonyx to Dehaanius MacLeay. 



Range: Eastern Pacific from Lagoon Head, west coast of Lower 

 California, and Puerto Refugio, Angel de la Guarda Island, Gulf of 

 California, to Acapulco, Mexico. Erroneously reported from Chile. 

 Western Atlantic from Indian River, Florida, to Desterro [or Rio de 

 Janeiro], Brazil. PBermuda (Verrill). Not South Africa [Epialtus 

 scutellatus of Miers (1886) and Stebbing (1910) is a Dehaanius, fide 

 Barnard (1950, p. 35)]. Shore to 17 fathoms. 



