97 



processes, and from the upper angle projects a considerably curved, moderately slender hook, 

 which is more than twice as long as the comb, distally bifid and on the concave margin with 

 a slender denticle. The lateral process is somewhat Iarge and distally very much curved, hook- 

 shaped, with a sharp tooth on the convex margin just beyond the curvature (fig. 36'); the distal 

 half of the median lobe is moderately broad but considerably narrovver than the proximal, not 

 folded and with the end rounded. The accessory lobe is well developed ; the setiferous lobe is 

 somewhat longer than the median, with the somewhat produced, triangular terminal part bearing 

 about 7 seta?, while the outer margin itself is naked. 



Length 8 — 9 mm. 



Remarks. — G. O. Sars referred this species to E. graci/is Dana, but as pointed 

 out in my Monaco-paper Dana's species is unrecognisable and cannot be the form described 

 by Sars, because Dana's form, according to his statement, was longer and its first antennular 

 joint was "sparingly produced and acute at apex". As Dana's types are lost, I cancelled the 

 name E. ^raei/is. 



E. tenera is easily distinguished from all other species hitherto known excepting about 

 half-grown specimens of the gibba-group (E. gibba G. O. Sars, E. pseudogibba Ortm., E. hemt- 

 gibba n. sp. and E. paragibba n. sp.). Adult or subadult males of E. tenera are of course 

 instantly separated from small specimens of the gibba-group by possessing copulatory organs 

 and by the lobe from second antennular joint; females may be separated by having the very 

 small eyes at least partly black and by having the third abdominal segment quite unarmed, 

 while the process on this segment begins to develop in rather early stages of E. pseudogibba 

 and allied forms. 



Distribution. — The species is known from many places in the tropical and sub- 

 tropical areas of the Atlantic and the Pacific. 



c. Species with a single pair of lateral denticles on the carapace and 

 with a dorsal process on the hind margin of third abdominal segment, 

 but without processes on the two following segment s. 



This group comprises 6 already established and several hitherto undescribed species, but 

 the "Siboga" collection contains only 4 species, 2 of which are new, while the third, E. Sibogee 

 H. J. H., is known only from a note without figures. 



10. Euphausia pseudogibba Ortm. PI. XIV, figs. 4a: — 4^. 



1893. Euphausia pseudogibba Ortmann, Decapoden und Schizopoden, in Ergebn. der Plankton- 

 Exped. der Humboldt-Stiftung. B. II, G., b., p. 12. Taf. I, Fig. 6. 



Stat. 118. July 13. Lat. i°38'N., long. i24°28'.2E. Hensen vertical net, from 900 m. to 



surface. 1 specimen. 

 Stat. 141. August 5. Lat. i°o'.4S., long. I27°25'.3 E. 1930 m. Hensen vertical net, from 



1500111. to surface. Many specimens, the majority only half-grown or still smaller. 

 Stat. 143. August 7. Lat. i°4'.5 S., long. I27°52.6E. 1454 m. Hensen vertical net, from 



IOOO m. to surface. 13 specimens, half of them adult. 



SIROGA-EXPED1TIE XXXVII. 13 



