90 • THE VOYAGE OF H.M.S. CHALLENGER. 



taken together. The preanal spiue (fig. 19) is exceedingly narrow and acutely 



pointed. 



The eyes (see fig. 20) are distinguished by their remarkably small >size, and almost 

 fusiform shape, the cornea not being at all expanded, and the greatest thickness occurring 

 in the middle of the pedicle. 



The antennular peduncle (fig. 13) does not exhibit any trace of dorsal lappets. 

 The basal joint is rather broad, but shorter than the two succeeding joints taken 

 together. The middle joint forms at the end, above, a slight projection, reaching 

 over the base of the terminal joint, and provided with a dense row of delicate 

 bristles. 



The antennal scale (fig. 14), slightly projecting beyond the second joint of the 

 antennular peduncle, exhibits an oblong-ovate form, with the apex narrowly truncate 

 and the outer corner unarmed. The basal spine is rather elongate, reaching nearly to 

 the middle of the scale, and is armed at the inner edge with a row of strong denticles. 

 The basal part of the flagellum appears rather powerful, but does not nearly attain the 

 length of the scale. 



The mandibular palp (fig. 15) has the terminal joint very small and oval in form; 

 it is armed with five ciliated spines on the inner edge, and a single bristle on the 

 outer. 



The first pair of maxillae (fig. 16) exhibit much the same appearance as in Euphausia 

 antarctica. 



The second pair of maxillae (fig. 17) have the terminal joint not very large, of 

 a rather regular ovoid form, and but sparingly supplied with bristles. 



The maxillipeds and legs exhibit, on the whole, the usual structure, and have the 

 outer joints somewhat flattened. 



The gills are comparatively simple in structure and provided with a somewhat 

 limited number of digitate lobules. The posterior pair (fig. 18), which, in other species, 

 are richly arborescent, consist of only three comparatively short branches, one of which 

 is bent inwards. 



The copulatory appendages to the two first pairs of pleopoda in the male are rather 

 strongly developed. Those on the first pair (fig. 22) have the outer process securiform, 

 or projecting into two hook-shaped processes, pointing in opposite directions ; the 

 middle one is strongly bent, and finely dentate at the tip ; the inner process finally has 

 the secondary hook serrate at the outer edge. The appendages of the second pair 

 (fig. 23) jut out into three rather broad and somewdiat twisted lobes, reaching considerably 

 beyond the apex of the principal plate. 



The telson (see fig. 21) exhilnts the usual slender form, and is armed with two pairs 

 of small dorsal denticles, exclusive of the subapical spines. The latter (broken oflF in the 

 specimen examined by Dana) are rather strong, but quite smooth and slightly divergent. 



