66 RATHBUN 



SPIRONTOCARIS MURDOCHI Rathbun. 

 Plate in, fig. 6. 



Hippolyte spinus MURDOCH, Report Internal. Polar Exped. to Point Barrow, 



Alaska, 140, 1885. Not Cancer spinus Sowerby. 

 Spirontocaris murdochi RATHBUN, Proc. U. S. Nat. Mus., xxiv, 893, 1902. 



Very near S. liljeborgii and S. spina. 



Female stout. Rostrum three fourths as long as carapace, not reach- 

 ing tip of antennal scale. Carapace cristate, except on posterior fourth, 

 and furnished with 3 or 4 large teeth. Midrib 

 of rostrum nearly horizontal ; tip acute ; upper 

 limb with convex upper margin, armed with 20 

 or 22 small irregular teeth ; lower limb, also with 

 dSl: 2 side 5 of carafe "" con vex margin, deeper than the upper, and fur- 

 <x ii). station 3650. nished with i to 4 small teeth near the extremity. 



Two supraorbital spines, one antennal, and one pterygostomian spine, 

 all well developed. 



Eyes of moderate size, slightly pyriform, the width of antennular 

 peduncle and half its scale. Antennular peduncle extending three fifths 

 the length of the antennal scale ; second segment twice as long as third ; 

 basal scale reaching nearly to end of second segment ; thickened portion 

 of outer flagellum reaching about to tip of antennal scale. Antennal 

 peduncle reaching slightly beyond the first segment of the antennular 

 peduncle; scale narrow-ovate, about as long as the rostrum, its spine 

 reaching about as far forward as the blade. 



Outer maxillipeds rather broad and reaching nearly to tip of acicle. 

 First pair of feet extending a little beyond antennal peduncle, the second 

 pair beyond acicle, fifth pair nearly to tip of maxilliped ; dactyli of last 

 three pairs long and slender, that of last pair half as long as propodus. 



Abdomen not carinate ; third segment produced well backward ; 

 fourth provided with a lateral spine ; sixth three fourths as wide as long, 

 and about three fifths as long as the seventh, which has 3 pairs of lateral 

 spinules. 



Male. The male differs from the female in the same manner as in S. 

 liljeborgii; it is smaller and slenderer than the female, rostrum and anten- 

 nules longer, dorsal teeth much reduced. 



Dimensions. $ , length 46.6 mm., length of carapace and rostrum 17 

 mm., of rostrum 7.5 mm. 



Distribution. Arctic coast of Alaska; Kamchatka; Okhotsk Sea. 

 Rare. Taken at the following localities : 



Lat. 71 02' oo" N., long. 1570 46' oo" W., 19 fathoms, i $ (U. S. R. S. 

 Corwin). 



