CALIFORNIA STALK-EYED CRUSTACEA. 171 



the third pair of pereopods. The process on the outer side of the base of 

 the auteunules is broad, irregiilarly ovate, and about reaches the tip of the 

 first joint; flagella longer than the peduncle, the inner one (and generally 

 the outer) exceeding the tip of the anteunal scale. Antennae as long as, 

 or longer than the body; acicle about two-thirds the length of the cara- 

 pace, with the antero-internal angle produced and rounded, extending as 

 far forwards as (often further than) the spine at the outer angle. The 

 external maxillipeds reach about as far forwards as the tip of the antennal 

 scale. The first pair of chelipeds generally extend about as far forwards 

 as the tips of the maxillipeds; merus with a spine near the middle of the 

 lower side; hand oblong, about twice as long as wide, with the edges sub- 

 parallel; the margin against which the finger closes is regularly convex 

 and more nearly transverse than longitudinal; spinous poUex directed 

 obliquely forwards. Third pair of pereopods slender and a little longer 

 than the second. Antepenultimate abdominal segment carinated above; 

 the sixth segment shows a tendency to become carinated and often has a 

 slight median groove. Telson grooved above, subacute at the tip, and 

 exceeding the sixth plus one-half of the fifth abdominal segment. Uropods 

 narrow, rounded at the tip, and equalling (commonly slightly exceeding) 

 the telson. An acute tooth on the sixth segment on either side of the 

 base of the telson and a spine at the posterior inferior angles, between 

 which there is a median ventral spine which is curved backwards; the 

 posterior three-fourths or more of the ventral surface of this segment is 

 marked by a groove. 



Color in life dark gray with a blackish tail. ^ 



Alaska to Lower California. 



This species differs from G. crangon of the Atlantic in 

 having the fifth and sixth abdominal segments cari- 

 nated above and in the groove on the under side of the 

 sixth segment. It is also distinct from C. affinis. Ajffinis 

 has a longer rostrum, a much narrower antennal scale, 

 a much narrower and more acute telson. In the speci- 

 men of ajffinis figured by Bate^ the distal end of the 

 hand is concave and is furnished with a tooth next to 

 the pollex. The corresponding portion of the hand in 

 nigricauda is evenly convex. 



I have examined the types of Lockington's Crangon 

 alaskensis. 



1 Challenger Reports, Vol. XXIV. PI. LXXXVI, fig. 1. 



