C A R I D E A. 



569 



infra 7-dentatum, cvpice bifidum. Pedes toti nudiusculi, Stii iti btique 

 longitudine sensim decrescentes, Stii longi, lmi articidis 2dorum tribus 

 primis paulo longioves. 



Carapax densely very short pubescent, margin below the eye with 

 two spines. Beak longer than basal scale of outer antennae ; ensi- 

 form, somewhat recurved, but apex not raised above level of back, 

 sixteen to eigh teen-toothed above, teeth small and continued nearly 

 to middle of back, towards apex unarmed, apex bifid, below seven- 

 toothed. Feet nearly naked, third, fourth, and fifth pair decreasing 

 regularly in length, anterior pair but little longer than first three 

 joints of second pair. 



Plate 36, fig. 8, animal, natural size. 



Straits of De Fuca, at Dungeness, Oregon. 



Length of body, five inches ; of carapax, two and one-fourth inches ; 

 of beak to the posterior tooth on the back, one and five-eighths inches ; 

 of beak to the orbital sinus, its proper base, one and one-fourth inches. 



Subfamily PALiEMONINiE. 



We have added several new genera to this subfamily ; and they 

 show the little importance of external form compared with certain 

 other characteristics. In the two extremes of the group, Pontonia 

 and Palaemon, we have a striking contrast in beak and body, the one 

 depressed, with a short beak, the other compressed, with a long ensi- 

 form beak ; in the former, the outer maxillipeds are suboperculiform, 

 in the latter, slender throughout. The genus Pontonia, as adopted 

 by Milne Edwards, embraces two genera ; one, Pontonia proper, with 

 small eyes, and living in the shells of living molluscs ; and the other, 

 swimming free, and often found among the branches of a coral, where 

 it had secreted itself. The latter (our CEdipus), has large eyes, with 

 the outer maxillipeds equally broad throughout, and the tarsus having 

 a high prominence below. Another group (Harpilius, as here adopted) 

 has probably been included under Pontonia ; but although near the 

 last in general form, and having also an uncinate tarsus, the promi- 



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