44 THE VOYAGE OF H.M.S. CHALLENGER. 



Esclisclioltz saw, and on the strength of which he gives as localities the South Atlantic 

 and South Pacific Oceans, are really referable to micans, seems to me open to doubt. 



3. Halobates princeps, n. sp. (PI. I. fig. 3). 



Oblong oval, widest behind the middle. Somewhat shining, silvery ash grey, espe- 

 cially on the sides and below. A reddish-yellow oblique mark on each side of the head 

 posteriorly. Middle acetabula, with the inferior margins, inner edge of suture, and 

 the adjacent part of the hind margin of mesosternum, as well as the hind margins of 

 the ventral segments, fuscous ochreous. Antennae and front legs black. Middle and 

 hind legs brownish -black. Antennae with second joint subequal in length to fourth, less 

 than twice as long as third. Front tarsus with first joint a little less than twice as long 

 as second. Middle tarsus with first joint more than three and a half times the length of 

 second. 



? . Length 5 "5, breadth 2 '3, middle femur 7, hind femur 5 mm. 



Habitat. ~-Ge\&\>&^ Sea. February 6th, 1875. One specimen. (Challenger.) 



Somewhat like Halobates uiiillerstorffl, but distinguished from that and other species 

 by its larger size and longer middle and hind legs, as well as by the long first joint of the 

 middle tarsus. 



? . Oblong oval, widest behind the middle. Slightly shining silvery ash grey, 

 brighter at the sides and below. Back of the head with an oblique, not very well-defined 

 reddish-yellow spot on each side. Anteunge and front legs black, with greyish pubes- 

 cence. The other legs brownish-black ; coxae and trochanters with silvery grey hairs, the 

 other joints with fuscous hairs. Eyes brown. Eostrum black. Margins of the middle 

 acetabula below, the adjacent part of the hind margin of the mesosternum, the inner 

 edge of the middle acetabular suture, and the hind margins of the ventral abdominal 

 segments fuscous ochreous. 



Antennce (PI. I. fig. 3, a.) about three-fourths the length of the body ; first joint 

 slender, subec[ual in length to the other three joints taken together; second joint slender, 

 about one-third the length of the first ; third joint more than one-half the length of the 

 second ; fourth subequal in length to second, stout and slightly attenuate upwards. 



Pronotum with front margin strongly and hind margin slightly concave ; disk with 

 a wide transverse fovea on each side anteriorly. 



Mesonotum widest behind the middle. 



Front legs with stout femora, thickest about the middle ; tibia subequal in length to 

 femur ; tarsus (PI. I. fig. 3, f.t.) subequal in length to the tibia, first joint a little less 

 than twice as long as the second, which is cleft between the base and the middle. 



