182 PROCEEDINGS OF THE ACADEMY OF [1895. 



(Owen, Stimpson); Northern Alaska: Point Barrow (Murdoch); 

 Bering Strait: Avatska Bay, 10-20 fath. (Stimpson); Greenland: 

 Godthaab (Kròyer); Labrador, (Smith); Gulf of St. Lawrence 

 (Smith); New Foundland: St. Johns (Stimpson); Nova Scotia, 59 

 fath. ; Halifax, 26-52 fath. (Smith). 



2. Nectocrangon alaskensis Kingsley, 1882. 

 Kingsley, Bull. Essex Inst. XIV, 1882, p. 128. 



Geographical distribution: Alaska, Kodiac Arch.: Marmot 

 Island (Kingsley). 



PONTOPHILUS Leach, 1815. s 



Pontophilus Leach, Melacostr. Podophth. Brit. 1815, pi. 37 A. 

 Egeon Risso (pr. part.) Hist. Nat. Europe mérid., V. 1826, p. 58. 

 Cheraphilus and Aegeon Kinahan, Proceed. E. I. Acad., Dublin, VIII, 1862, 

 p. 68, 69. 



Second periopoda shortened, carpal joint and hand together not 

 longer than merus, chelae present. Eyes present, free. Gills seven 

 on each side: six pleurobranchise (i. k. 1. m. n. o.) and one (rudi- 

 mentary) podobranchia (h. ). 



a x . Median keel of carapace with more than three spines. Seven 

 keels on the carapace, with numerous teeth. Abdomen strongly 

 sculptured. 



6j. Rostrum emarginate P. cataphractus (4). 



b 2 . Rostrum acute, with lateral teeth P. bengalensis, 



P. andamanensis. 9 

 a. 2 . Median keel of carapace with three spines. Abdomen smooth or 

 only the posterior segments with longitudinal keels. 

 6j. Carapace with more than two lateral spines. Abdominal seg- 

 ments with distinct keels. 

 c\ Three denticulate lateral keels on each side. Fifth segment of 

 abdomen with a keel. Rostrum acute, simple . P. echinulatus. 

 e 2 . Two lateral keels on each side, the upper with three, the lower 

 with two spines. Third and fourth segment of abdomen with 

 a simple keel, fifth with four, sixth with two keels. Rostrum 



with lateral teeth P. spmosus (3). 



c 3 . Two lateral keels, the upper with two, the lower with one 

 spine, 

 dj. Sixth segment of abdomen with a double keel. Rostrum 



without lateral teeth P. norvegicus (4). 



d 2 . Fifth segment of abdomen with four, sixth with two keels. 

 Rostrum with lateral teeth P. brevirostris. 



9 I am not sure whether these two species {bengalensis and andamanensis) 

 really belong to Pontopliilus. 



