46 Benedict Arcturidse in the U. S. National Museum. 



Arcturus glabrus sp. nov. 



The head is wider than long, measured in the constriction in front of 

 the eyes and on the median line, but longer than wide if the side of the 

 head is taken. 



The antennae are longer than the body in both sexes ; much longer in 

 the female than in the male. 



There are no spines or tubercles on the head or posterior to it. The 

 segments of the thorax and abdomen are smooth 

 to the eye and are finely reticulated under a lens. 

 The fourth segment differs in the sexes ; in the 

 male it is a little longer and more slender than 

 the two preceding segments taken together; in 

 the female it is shorter and stouter ; so different 

 is the appearance that the sexes can be readily 

 separated in a dorsal view. The anterior margins 

 of the second, third, and fourth segments are 

 notched on the median line. 



The abdomen is composed of two segments, an- 

 chylosed, the usual second segment being only in 

 dicated by a swelling above and a short suture at 

 the side. There are no lateral projections on the 

 abdomen ; the epimera of the posterior part of the 

 thorax cannot be seen from above. The dactyls 

 of the posterior feet are bi ungulate. The length 

 of the body of a male is 31 mm. ; of the antennae 

 38 mm. ; female, body 28 mm. ; antennae 45 mm. ; 

 female, body 24 mm. ; antennae 39 mm. 



A number of specimens of this species were 

 taken by the 'Albatross ' at Station 3599, in Bering 

 Sea, lat/N.5205 / , long. \V. 17740 / ,in 55 fathoms 

 (No. 20529 U.S.N. M.). 



Arcturus beringanus sp. nov. 



The head is excavated in front ; the lateral projections are broad ; deep 

 constrictions or depressions exist both in front and behind the eyes. The 

 antennae when laid off on the body reach the base of the abdomen ; the 

 fourth and fifth articles are very long; the flagellum is composed of seven 

 or eight articles ; the anten- 

 nulae reach to the end of the 

 second article of the antennae. 



The first and last three seg 

 ments of the thorax are near 

 ly equal in length ; the fourth 

 segment is a little more than FIR- r>. Arcturus beringa***- (X 2%.) 



twice as long as any of the others. The posterior margins of the seg 

 ments are concave on each side of the median line to the posterior angle 

 of the segments, making a more or less acute point at the middle of the 

 segment and lobate posterior angles. 



FIG. 5. Arcturus glabrus, 

 (X 1%.) 



