170 CALIFORNIA ACADEMY OF SCIENCES. 



Family CRANGONID^. 



Mandibles slender, incurved, not divided at the apex, and devoid of a 

 palp. External maxillipeds pediform. First pair of pereopods stouter 

 than the second and subchelate, the dactyl closing against the margin of 

 the hand, the pollex spiniform; second pair slender, simple or chelate, the 

 carpus entire; all of the succeeding pairs simple. 



Genus Crsingon Fahr. 



Rostrum very short and dorsally flattened. Eyes free, Antennules 

 biflagellate. First pair of pereopods stouter than the second and but little 

 longer. Third pair of pereopods slender, subequal to the first pair in 

 length, and terminating in a styliform dactyl; the last two pairs are stouter 

 than the third, and have long, more or less flattened dactyls. Branchiae 

 five. 



Type. — C. crangon (Linn.). 



X Crangon nigrieauda St. 



Crangon vulgaris Owen (non Fabr.), Zool. Beechy's Voyage, 1839, p. 87. 

 Dana, Crust. U. S. Expl. Expd., Part I, 1852, p. 536. Bate, in Lord's 

 Nat. in Vancouver's Is., Vol. II, 1866, p. 278. Smith, Rep. Prog. Geol. 

 Sur. Canada, 1878-9, B, p. 212. Kingsley, Bull. Essex Inst., Vol. 

 XIV, 1883, p. 129. Rathbun R., The Fisheries of the U. S., Sec. I, 



1884, p. 817. Murdoch, Rep. Int. Polar Expd. to Pt. Barrow, Pi. IV, 



1885, p. 138. Bate, Challenger Reports, Vol. XXIV, 1888, p. 485. 

 Crangon nigrieauda Stimpson, Proc. Cal. Acad. Sci., Vol. I, 1856, p. 89; 



Journ. Bost. Soc. Nat. Hist., Vol. VI, 1857, p. 496, PI. XXII, fig. 6. 



Streets and Kingsley, Bull. Essex Inst. Vol. IX, 1877, p. 108. 



Kingsley, Ihid., Vol. X, 1878, p. 54. Lockington, Ibid., Vol. X, 1878, 



p. 159. 

 Crangon ( Steiracrangon ) nigrieauda Kinahan, Trans. Roy. Irish Acad., 



Vol. XXIV, 1862, p. 57; Proc. Roy. Irish Acad., Vol. VIII, 1864, p. 68. 

 Crangon alaskensis Lockington, Proc. Cal. Acad. Sci., Vol. VII, 1877, p. 



34. Kingsley, Bull. Essex Inst., Vol. X, 1878, p. 54. 

 Crangon crangon affinis Ortmann, Proc. Acad. Nat. Sci. Phila., 1895, p. 180. 

 Crangon vulgaris Linn., var. affinis De Haan, Walker, Trans. Liverpool 



Biol. Soc, Vol. XII, 1898, p. 275. 



Carapace with a spine on the gastric area and one on each hepatic region, 

 the three situated in a transverse line. Rostrum short, grooved above, 

 and rounded at the tip. Suborbital and antennal spines present, the latter 

 the larger. Thoracic sternum furnished with a spine between the bases of 



