THYSAXOPODA OBTUSIFKONS. 215 



mens from four localities in the Eastern Atlantic between Lat. 28° N. ami Lat. 

 23° N., besides from the Central Atlantic at Lat. 5°-7° 15' N., long. 30° W., from 

 Southern Atlantic at Lat. 30j° S., long. 22^° W., finally from five Stations in an 

 area across the more southeastern part of the Indian Ocean, viz. between Lat. 

 22|° S. and 27^° S., long. 80° E. and 103° E. From the Hawaiian waters (the 

 label has Sta. 3808. From between Erben Bank to Kaiwi C'liannel) I have seen 

 nine specimens belonging to this species but referred l)y Ortmann (1905) to T. 

 obtusifrons G. O. S. In the area explored in 1904-1905 this species is confined 

 to the southern part, not going North of Lat. 9l° S. — The specimens in the 

 Copenhagen Museum have certainly all been taken at the surface during night. 



6. Thysanopoda obtusifrons G. O. Sars. 



Plate 4, figs. .5a-of. 



1883. Thijsannpnda ohhmfrons G. O. Sars, Forh. Vid. Sel,«k. Chri«!tiania for 1883, no. 7, p. 21. 



188.5. Thysanopoda ohtusifrons G. O. Sars, Challenger Rejjt., 13, p. 102, pi. 12, figs. 1-14. 



1905. Thysanopoda vulgaris H. J. Hansen, Bull. Mus. Ocean. Monaco, no. 30, p. 15. 



1905. Thysanopoda vulgaris H. J. Hansen, Bull. Mus. Ocean. Monaco, no. -12, ji. 20. 



1910. Thysanopoda obtusifrons H. J. Hansen, Siboga-Exp., 37, p. 81. 



Sta. 4683. Dec. 9,1904. Lat. 20° 2.4' S., long. 91° 52.5' W. 300 fms. to surface. 7 specimens. 

 Sta. 4685. Dec. 10, 1904. Lat. 21° 36.2' S., long. 94° 56' W. 300 fms. to surface. 11 specimens. 



Sta. 4687. Dec. 11, 1904. Lat. 22° 49.5' S., long. 97° 30.6' W. \ ^""Z^- '° ''''^:^''^- ^^ «P^«'"^"«- 



( 212.:j fms. to surface. 3 specimens. 



Sta. 4689. Dec. 12, 1904. Lat. 24° 5' S., long. 100° 20' W. 300 fms. to surface. 2 specimens. 



Sta. 4691. Dec. 13, 1904. Lat. 25° 27.3' S., long. 103° 29.3' W. 300 fms. to surface. 4 specimens. 



Sta. 4695. Dec. 23, 1904. L.at. 25° 22.4' S., long. 107° 45' \V. 300 fms. to .surface. 2 specimens. 



Sta. 4701. Deo. 26, 1904. Lat. 19° 11.5' S., long. 102° 24' W. 300 fms. to surface. 2 specimens. 



Sta. 4730. Jan. 20, 1905. Lat. 15° 7' S., long. 117° 1.2' W. 300 fms. to surface. 1 specimen. 



Sta. 47.32. Jan. 21, 1905. Lat. 16° 32..5' S., long. 119° .59' W. 300 fms. to .surface. 2 specimens. 



Sta. 4740. Feb. 11,1905. Lat. 9° 2.1' S., long. 123° 20' W. .300 fms. to surface. 1 specimen. 



Description. — The frontal plate (figs. 5a-5b) is considerably produced, 

 about twice as broad as long, broadly obtuse, with the front margin rounded 

 or a little angular at the middle and somewhat shorter than one of its oblicjue 

 lateral margins; on its end is seen the rostrum transformed as a small, vertical, 

 conical tooth or at least a vestige of such a tooth: the plate is thick, longitudi- 

 nally concave at the middle, so that a pair of sul)median olituse keels, united 

 in front at the rostrum mentioned, is formed, and a little l)ehind the rostrum 

 begins a rather low median keel which is highest consideral)ly behind the end 

 of the submedian keels and occupies about two fifths of the length of the cara- 

 pace. The carapace has a minute, but distinct, denticle on the outer side of 

 the lateral margin somewhat before its posterior end, while the produced jiart 

 of the anterior margin above the antennae is only a minute tooth; a furrow 

 runs close to the lateral margin along its entire length and liends upwards along 

 a portion of the posterior margin, but the carapace has no other grooves. 



