356 THE GENUS PANOPEUS BENEDICT AND RATHBUN. 



Panopeus, as the exposure of the seventh sternal segment varies with 

 the species, as does the size of the palatal ridge. The two species 

 which have been placed in Enrytlum have but little in common, except 

 the two rounded lobes of the front. It would seem that if a division of 

 the genus Panoi)eus shoukl eventually be made, it must be on other 

 lines and more definite characters. It can hardly be said that we have 

 extended the limits of a genus which already contains Panopeus herbstii 

 and P. harrisii. 



The genus is American with the exception of one species from the 

 west coast of Africa and two from the Indo- Pacific region. 



The first species was described and figured by Thomas Say, in Jour. 

 Acad. Nat. Sci. Phila., i, 1817, under the name of Cancer panope Herbst, 

 to which species he had mistakenly referred it. Milne Edwards, in his 

 classical work published in 1831, established the genus Panopeus^ and 

 under the name of P. lierhstii entered as synonyms Cancer panope Herbst 

 and C. panope Say, believing them to be one and the sanie species, thus 

 continuing the mistake of Say, which has been followed by numerous 

 authors. Prof. S. I. Smith, in the Proc. Boston Soc. Xat. Hist., xii, 

 18G9, points out the error, and in 1872 Prof, von Martens in the Arch, 

 fur Xatur,, 38, refers to the original specimen of Cancer panope Herbst 

 in the Berlin Museum as a Menipjpe^ thus confirming the view taken by 

 Professor Smith. 



In the waters of Long Island Sound the indigenous species are found 

 abounding on the oyster beds, very often in the dead shells of oysters 

 and other lamellibranchs when the valves remain together and partly 

 open. They move slowly and clumsily, and no doubt remain for long 

 periods in the same place of concealment, watching for food to come to 

 them. Farther south they are found near high-tide mark in holes in 

 the banks along with Qelasimus and Sesarma. In deeper water they 

 live among sponges, corals, dead shells, and clusters of oysters, or in 

 any object that will afford concealment. Many of the species are not 

 easily distinguished and only careful comparison will acquaint one with 

 them. We have examined over three thousand si»ecimens belonging to 

 the different si)ecies which we have referred to Panopeus. 



In the following descriptions the antero lateral teeth are designated 

 as first, second, third, and fourth. The first is the tooth next the outer 

 anglQ of the orbit, and the fourth is the posterior tooth. 



The numbers in parentheses after the names of localities are taken 

 from the catalogue books of the National Museum. Wherever it was 

 impossible to verify the synonymy, we have placed the quotation in 

 parentheses. 



GENUS PANOPEUS Milue Edwards. 



Cancer. Thomas Say, Jour. Acad. Nat. Sci. Phila., i, p. 57, 1817. 



Panopeus. Milne Edwards, Hist. Nat. des Crust., i, p. 403, 18o4. J. E. DeKay, Crust. 



ofN.Y..p.5, 1844. Gay. Historia de Chile, ZoiJl., in, p. 138, 1849. H. Lucas, Hist. 



Nat. des Crust., p. 89, 1851. J. D. Dana, Crust. U. S. Ex. Ex., pp. 149, 179, Idb-Z. 



