coKopiniD.K. 263 



propodos, its npcx impinp^inp: iiijainst the infcro-distal anplo of the 

 carpiLS. Hody Itlackisli, with irrogidar pale spots. Antenna? and 

 aj)pendafccs white, joints tipped with blackish. Two hind pairs 

 [pleopoda '?] white. 

 " Length -^ of an inch. 



" Hab. United States of N. America. Living in a free, cylindrical, 

 membranaceous, diaphanous tube.'' — Say. 



Say states the upper antenna^ to be four-, the lower five-jointed ; 

 and M. -Edwards thereupon constituted his genus Enchthonius, as 

 possessing a short flagellum. It has been usual with some naturalists 

 to deseribe the flagellum itself as a joint, and to distinguish it as 

 bemg di^•ided into segments. I have therefore considered Say's 

 apical 'joints' to the antenna) as true flagella, which appears to 

 coincide with the descriptions by Tcmpleton and Stimpson. 



2, Cerapus abditus. (Plate XLV. fig. 2.) B.M. 



Cerapus abditus, TempUiun, Trans. Ent. Soc. i. p. 188. pi. 20. f. 5. 

 Cerapodina abditus, Edwards, Hist, des Crust, iii. p. 62. 

 Erichthonius diffonuis, Spcnce Bate, Si/nopsis, i^-c, An7i. Nat. Hist. 

 Feb. 18o7 (not Edwards). 



Wliite, Hist. Brit. Crust, p. 196. 



Eyes diagonally ovate, red. Antennae subequal, scarcely half the 

 length of the animal : inferior paii" having the last thi-ee joints of 

 the peduncle gradually increasing in length; flagellum scarcely 

 as long as the last joint of the peduncle. First pair of gnathopoda 

 having the coxa small ; carpus broad, and continuous with the 

 propodos ; propodos subtriangulate, being as broad as the cai-pus 

 at the near extremit}^ and rapidly tapering to the distal extremity ; 

 palm convex ; dactylos arcuate, serrated. Second pair of gnatho- 

 poda very large, having the carpus very large, and continuous \\\i\\, 

 but much longer and broader than, the propodos, — the inferior 

 margin anteriorly produced to a large double-pointed process, 

 against which the apex of, the dactylos impinges ; propodos scarcely 

 more than half as broad as the cai-pus ; palm occupying the entire 

 length of the inferior margin, irregidarly waved ; dactylos slightly 

 curved, with the inner margin distended. First two paii-s of 

 pereiopoda short, having the basa dilated as largely as in the three 

 posterior, and the propodos and dactylos gradually decreasing 

 to a sharp point : third pair having the propodos cidarged at the 

 extremity and furnished with a stout sjiine ; dactylos short, ro- 

 bust, arcuate : the last two pairs like the third, but lunger and 

 more slender. Antepenultimate and penultimate pairs of pleopoda 

 styliform, terminating in sharp straight spines ; the penidtimato 

 shorter than the preceding : ultimate very strong, being broad at 



