1 900.] FROM THE FALKLAND ISLANDS. 545 



In the second group we observe : — 



Carapace with postero-dorsal tooth . E. schotti Ortmann. 



Uropods reaching apex < Eyes large E. gibboides Ortmann. 



oftelson. | Eyes small E. pseudogibba Ortmann. 



Fifth and sixth pleon-segments with indentured 



hind margin E. spinifera Sars. 



Third pleon-segment with dorsal tooth strong E. mucronata Sars. 



First antenna? with basal 



leaflet acute, bifid E. gibba Sars. 



First antennae with basal 



leaflet rounded, simple E. valient ini, n. sp. 



Third pleon-segment 

 with dorsal tooth • 

 weak. 



Euphausia vallentini, n. sp. (Plate XXXVII.) 



Rostral projection acute, short, not nearly reaching apex of eyes. 

 Carapace with slight longitudinal elevation behind the rostrum ; a 

 single tooth on lateral margin at about the middle. Third pleon- 

 segment produced backward in a thin, almost spine-like, tooth 

 of no great length, so as easily to escape notice. Fifth pleon-seg- 

 ment with postero-lateral corners rounded, not quadrate as figured 

 by Sars in E. gibba. Sixth pleon-segment nearly as long as fourth 

 plus fifth. The preanal spine tridentate, the lowest tooth much 

 the largest. In one specimen out of four the upper teeth seemed 

 to be represented only by a tubercle. 



The eyes are pear-shaped, of medium size. 



First antennae.— The first joint is longer than the second plus 

 the third and has at the apex a smoothly rounded membranous 

 leaflet, with a group of setae adjacent on the inner side, and on the 

 outer a strongly projecting angle furnished with various plumose 

 setas. The third joint has a small apical lobe on the underside 

 and a membranous expansion along the upperside. 



Second antennas. — The scale extends well beyond the peduncle, 

 the basal spine not nearly reaching the middle of the scale and only 

 feebly pectinate on its inner margin. 



Mandibles. — Cutting-edge broad and thin, with two prominent 

 teeth at the top, of which both are double in one mandible, but 

 only the upper one in the other ; the molar prominent, its cylindri- 

 cal crown radiated with finely pectinate teeth ; palp strong, third 

 joint about two-thirds of second, fringed on one margin with 

 numerous spiues, the second joint carrying setae. 



Lower lip. — The inner margin of each lobe with a fur of very 

 short hairs extending nearly to the distal angle. 



First maxillae. — Unless by the greater breadth of the outer lobe, 

 these maxillae are not easy to distinguish from those which have 

 been figured for other species. 



Second maxillae. — The part which seems to vary most in the 

 several species is the terminal joint or palp. It is here distinguished 

 by its very considerable size, and by its shape, which is more that 

 of a parallelogram, with obliquely truncate apex, than is shown in 

 any other species for which these maxillae have been figured. Sars 

 says of E. gibba that " the oral parts aud the legs would not seem 

 to exhibit any essential difference from those of Euphausia gracilis." 



