Description of Genera and Species. 63 



bent backwards; their front margins l)ulge somewhat in front of the pivot. The 

 succeeding ones are each in turn less deep and more directed backwards. Those of the 

 sixth segment are small and do not extend to the posterior margin. All have a thickened 

 band or facet where overlapped. 



The telson, which does not extend to the tip of the external branch of the uropods. 

 is heart-shaped, with a tumid base and applanated posterior region, which is fluted by a 

 raesian depression flanked with carinated ridges and ends in a median elongation, and is 

 probably supplied with a pair of narrow articulated plates or accessory swimmerets at 

 the base of the terminal lobe, like those of the modern Euphausiids (figs. 5, 8). 



The eye is large, and is usually seen in a crushed state lodged in its socket near 

 the inner angle of the rostrum. The antennular peduncle is enormously developed, 

 strongly resembling those of the modern congeners of the species. The proximal joint 

 is the largest and is flattened and hollowed out, and bent up near the base to form, with 

 the anterior margin of the carapace and the wings of the rostrum, a very efficient 

 protecting socket for the eye. Beyond the hollow for the eye the joint becomes nearly 

 cj'lindrical and extends to near the tip of the rostrum. The middle joint is much 

 shorter than the former one, and is oblong when flattened and traversed by a longi- 

 tudinal ridge. The distal joint is the shortest and is contracted along the mid-line, 

 and supports two short flagella ; but it has not been observed which of the two is the 

 longer. The antennal system is more like that of the true Caridea. Only the joint of 

 the peduncle bearing the basal scale has been observed. The scale is of the ordinary 

 caridean type, with an external strengthened part ending in a tooth or spine, the inner 

 being fimbriated and set with setaj. Along the edge there is a transverse suture and a 

 terminal fimbriated lobe fringed with setaj, the end of the scale extending to the tip of 

 the rostrum. The peduncle of the lash is three-jointed, the proximal joint being 

 narrow and wedge-shaped. The other two are elongated and of about equal length, 

 but do not extend as far as the tip of the scale. The flagellum is much more massive 

 than those of the antennules, and also much longer ; but the exact length has not been 

 made out, as they are generally insufficiently preserved. The body of the mandible is 

 large and set at an acute angle to the axis of the body. Its presence is nearly always 

 conspicuously shown by its collapse; but the details of the cutting and molar parts 

 have not Ijeen observed. The palp is long and slender and three-jointed, and is well 

 seen in fig. 8 as it lies outside the body and free from the other members. The first or 

 proximal joint is as long as the other two combined. The maxilla3 are unobserved 

 The maxillipede, known only by its endopodite, is the most massive limb of the trunk 

 (figs. 1, 2, 3). Four of its joints are often exposed; the tip joint is heart-shaped or 



