ME. E. J. MIEES OK THE IDOTEID^. 73 



The body is ovate, convex, posteriorly acute, of very firm con- 

 sistency. The head is tuberculate above, the elevations defined 

 by deep grooves ; its frontal margin is nearly straight, and is 

 armed with two rounded tubercles in the middle, between the 

 bases of the antennules ; its antero-lateral lobes are rather pro- 

 minent. The segments of the thorax have each a tubercle in the 

 median dorsal line; a longitudinal depression on each side appears 

 to mark the line of coalescence of the epimera ; on the sides 

 there is a less-marked but larger elevation, and the lateral mar- 

 gins are defined by a raised line ; the postero-lateral angles of 

 all the segments are but little prolonged backward, and are more 

 or less rounded. The postabdomen does not equal in length the 

 four posterior thoracic segments ; it has a median elevation on 

 the dorsal surface near its base, and three impressed lines appear 

 to mark with, more or less distinctness as many coalescent seg- 

 ments ; beyond these the dorsal surface is nearly smooth, convex, 

 with the lateral margins slightly sinuated and converging rapidly 

 to the distal extremity, which is subacute. Eyes large, but with 

 a small pigment-spot. Antennules rather widely separated at 

 base, reaching beyond the end of the peduncle of the antennae, 

 with their basal joints very short and scarcely dilated. Antennae 

 with the peduncle slender ; the last two joints nearly equal and 

 each longer than either of the preceding; flagellum minute, 

 3-jointed, not half as long as the last peduncular joint, with its 

 basal joint much longer than the two following, the last termi- 

 nating in a pencil of rather long setae. Legs slender, rather 

 thinly clothed with hair, and with very long, slender, simple 

 claws. The oblique raised line on the basal opercular plates 

 extends over the posterior two thirds of their outer surface. The 

 terminal plate is very narrow, triangulate, and acute at its distal 

 end. Length of the largest example about 1-^ inch (30 millim.), 

 breadth rather more than y^^- inch (11 millim.). 



This species, as far as its range is at present known, is confined 

 to the Straits of Magellan and the Falkland Islands. 



There is in the Museum collection an example, preserved 

 dry, from the Falkland Islands (W. E. Wright), designated by 

 White Anisonotus falMandicus, and four males preserved in 

 spirit from Gregory Bay, eastern Magellan Straits (Dr. B. O. 

 Cunningham). 



