422 PROCEEDINGS OF THE ACADEMY OF [1879. 



Sub-Family Pandalinse. 



Antennulse biflagellate, mandibles with a palpus, anterior pere- 

 iopoda very slender, not chelate ; second filiform chelate ; carpus 

 multiarticulate. 



o Genus Pandalus Leach. 1 Type Pandalus montagui Leach. 



Sub Family Palaemoninae. 



Two anterior pairs of pereiopoda chelate ; carpus of none annu- 

 late ; second pair larger than the first, pereiopoda without palpi. 



Section I. Mandibles without a palpus. 



A. Antennulse biflagellate. 



Genus Typton Costa.' 2 Rostrum small, eyes free, antennal scale 

 absent, external maxillipeds pediform, with exognath. Type 

 Typton spongioid Costa. 



o Genus Pontonia Latreille. Rostrum short, ej'es prominent, 

 antennulse with the outer flagellum bifid at the extremity; anten- 

 nal scale moderate. External maxillipeds suboperculiform with 

 exognath; second joint broad, longer than remaining joints to- 

 gether, these last cylindrical. Type Pontonia custos (Forskal sp.). 

 Guerin. Pontonia tyrrhena (Risso sp.) Latreille. 



Pontonia unidens, sp. n. (PI. xiv. f. 9.) Carapax pubescent, 

 depressed ; rostrum short, acute, slightly depressed, not extend- 

 ing as far forward as the eyes ; orbital spine present though small ; 

 cervical suture well marked; eyes stout, reaching the last joint 

 of the antennular peduncle. Antennulse with the joints of the 

 peduncle sub-equal ; the flagella very short, not as long as the 

 peduncle. Antennal scale about twice as long as broad, ex- 

 tremity rounded and reaching to the last joint of antennular pe- 



1 Pontophilus Risso, Hist. Nat. Europe Merid. t. v. p. 63, 1826 ; Brandt 

 in MiddendorfFs Reise in den Ausseisten Nordeii uud Osten Siberiens, 

 Bd. ii. Theil i. p. 122, 1851. 



2 Annali dell' Acad. Segli Aspir. Natur di Napoli ii. 1844 (Teste Heller). 

 Pontonella Heller, Verbandlungen des Zool. Bot. Verein in Wein, 1836, 

 p. 624. Rev. A. M. Norman (Aim. and Mag. Nat. Hist. IV. ii. p. 176, 

 1868) compares this genus with AlpJieus. It is far more nearly related to 

 Pontonia. Its resemblance to Antonomea, in the absence of the antennal 

 scale, was noticed by Heller. 



