coKorTiiTn.T;. 259 



4. DERCOTHOE ( =CERAPUS 2 )• 

 Dercothoe, Da/ia, U. S. Explur. Expcd. p. 908. 

 " Cox* modonitely largo ; fiftli nearly equally two-lobcd, and hardly 

 shorter than the fourth. The lateral margin of the front, which 

 beai-s the eye, often very salient. Posterior pair of plcopoda quite 

 simple, rather long; branch short, with a relaxed apex beaiing 

 two very short spines. Superior antennae usually the longer, ap- 

 pendiculatc . ' ' — Da na . 



The individuals comprised in this genus arc undoubtedly females of 

 Cercqnui ; but since the males of many species have not yet been 

 recognized, it may be convenient for a time to retain the name of 

 Dercothoe. Kroyer* remarks that Erichthonivs of Edwards (which 

 in this Catalogue is considered a sjiionym of Cerapus) is the male of 

 Podocerus. The general resemblance of the female of Cerajrusf to 

 Podocerus is considerable. Its difference consists chiefly in the absence 

 of the inner ramus to the posterior pair of pleopoda, the prolongation 

 of the carpus of the second pair of gnathopoda upon the inferior mar- 

 gin of the propodos, and the form of the telson ; hence it is not difficult 

 to assume that Kroyer's observation relates to the female of Cerajyus, 

 that is, to Dana's genus Dercotlioe. 



The male and female of Podocerus bear a considerable resemblance 

 to each other, and cannot be confounded with any other genus ; and 

 when Stimpson published his ' Natiu-al History of the Marine Inver- 

 tebrata of Grand Manan,' he must have been aware of these facts ; 

 but it does not appear that he fully appreciated their importance. 



1. Dercotlioe (Cerapus) emissitius. (Plate XLIV. fig. 7.) 

 Dercothoe emissitius, Dana, U. S. Explor. Exped. p. 969. pi. GO. f. 9. 



" Body slender. Cephalon oblong, with an ocular prominence on the 

 front margin, each side. Antenna) setose : the superior pair hardly 

 longer than haK the body ; first and third joints subequal, second 

 longer ; flagellum not longer than the base, possessing about seven 

 articuli ; secondaiy appendage having three articuli : inferior 

 pair shorter ; base about as long as the base of the superior pair ; 

 third and foui'th joints subequal, second short; flagellum shorter 

 than the base, possessing about seven articuli. First pair of gna- 

 thopoda quite small, having the propodos very narrow : second pair 

 strong ; propodos large, subovate, sparsely setose, above sparingly 

 arcuate, palm not at all excavate ; dactylos half as long as the pro- 

 podos. Three posterior pairs of pereiopoda gradually increasing in 

 length, setae few ; the tliird paii* shorter than the second. 



" Length 4 lines. 



" Hah. Sooloo Archipelago, dredged in G? fathoms water. Collected 

 February 2, 1842."— Z>anrt. 



» Nat. Tidskr. iv. p. 163. t Vide p. 2Gf> (C. diffonnis, fern.). 



s2 



