THYSANOPODA OBTUSIFRONS. 215 



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

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

 Southern Atlantic at Lat. 30^° 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 Channel) I have seen 

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

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

 to the southern part, not going North of Lat. 92° 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-5f. 



1883. Thysanopoda obtusifrons G. O. Sahs, Forh. Vid. Selsk. Christiania for 1883, no. 7, p. 21. 



1885. Thysanopoda obtusifrons G. O. Sars, Challenger Rept., 13, p. 102, pi. 12, figs. 1-14. 



1905. Thysanopoda vulgaris H. J. Hansen, Bull. Mus. Oc6an. Monaco, no. 30, p. 15. 



1905. Thysanopoda vulgaris H. J. Hansen, Bull. Mus. Oc6an. Monaco, no. 42, p. 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. 



^ . .„„. T „„o .„ ,, o, , ^.to n/^ /./ TTT ^ 300 fms. to .surface. 6 specimens. 

 Sta. 4687. Dec. 11, 1904. Lat. 22° 49.5' S., long. 97° 30.6' W. ^ „,,,. , . , ., • 



' • o ( 2125 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. Lat. 25° 22.4' S., long. 107° 45' W. 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. 4732. 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 oblique 

 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 submedian obtuse keels, united 

 in front at the rostrum mentioned, is formed, and a little behind the rostrum 

 begins a rather low median keel which is highest considerably 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 part 

 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 bends upwards along 

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



