34 U.S. NATIONAL MUSEUM BULLETIN 260 



tlie less strongly developed dorsal teeth of the pereon and pleon, and 

 the presence, on each side of the head, of two acute teeth shorter than the 

 rostrum. The shapes of the sixth and seventh articles of gnathopod 1 

 also differ from those of L. chrysotheras. 



The presence of lateral cephalic processes is characteristic of L. 

 arctica arctica Schellenberg. Specimens at hand resemble that species 

 closely but several small differences of subspecific importance occur 

 in various structures. The lateral pair of cephalic processess is shorter 

 than those of L. a. arctica; three large teeth occur on each of pleonites 

 1-3 instead of one large and one small, although L. a. arctica has the 

 remnant of a third tooth on pleonite 1 ; the cleft of coxa 1 on L. a. arc- 

 tica is much deeper than on L. a. turpis. 



Juvenile specimens show the close relationship of the two subspecies 

 more clearly than do adults. The accessor}^ cusps on the dorsal body 

 surface of a youthful specimen, 4.6 mm long from 7229, are rudi- 

 mentary as in L. a. arctica^ and three specimens about 3.7 to 4.0 mm 

 long from 7358 lack accessory teeth altogether. In juveniles coxa 1 is 

 more deeply bifid and coxa 2 more slender than in adults. The relative 

 difference between the length of the rostrum and the lateral cephalic 

 processes is less apparent in juveniles than it is in adults. 



Probably the specimen of L. arctica figured by Gurjanova (1951) 

 from the Polar Basin should be relegated to subspecific status also. 



Distribution. — Middle Baja California, 1205-2667 m. 



Liljeborgiidae 



Liljeborgia Bate 



Liljeborgia cota J. L. Barnard 



Figure 1 j-o 

 Liljeborgia cota J. L. Barnard, 19G2b, pp. 83-86, figs. 8, 9 ; 1966a, p. 64. 



These small specimens, 4.0 mm long, differ from the large and sup- 

 posedly terminal adults described by Barnard in having much larger 

 dorsal teeth of the pleon, the shorter fifth article of antenna 2, the 

 shorter and stouter fifth article of gnathopod 1, the weakly differenti- 

 ated gnathopods and the more slender tooth of the third pleonal epi- 

 meron. These specimens resemble L. flsslcorms (M. Sars) (see G. O. 

 Sars, 1895, pi. 189) but, like adults of L. cota^ differ from L. fi.ssicornis 

 in the shorter cleft of the telson and the nonerect teeth of urosomites 

 1 and 2. 



A fragmental specimen from 7235 is probably not L. cota; it has 



