218 THE SCHIZOPODA. 



7. Thysanopoda pectinata Ortmann. 



Plate 5, figs, la-lm. 



1893. Thysanopoda pectinata Ortm.\nn, Ergebn. der Plankton-Exped., 2, G., b., p. 10, taf. 1, fig. 4. 

 1905. Thysanopoda pectinata H. J. Hansen, Bull. Mils. Ocean. Monaco, no. 42, p. 25. 

 1909. Parathysanopoda Joliijera Illig, ZooI. Anz., 35, p. 225 (young). 



Sta. 4681. Dec. 8,1904. Lat. 18° 47.1' S., long. 89° 26' W. 300 fms. to surface. 1 specimen. 



Sta. 4687. Dec. 11, 1904. Lat. 22° 49.5' S., long. 97° 30.6' W. 300 fms. to surface. 1 specimen. 



Sta. 4?589. Dec. 12, 1904. Lat. 24° 5' S., long. 100° 20' W. 300 fms. to surface. 2 specimens. 



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



Sta. 4705. Dec. 28, 1904. Lat. 15° 5.3' S., long. 99° 19' W. 300 fms. to surface. 14 specimens. 



Sta. 4719. Jan. 14, 1905. Lat. 6° 29.8' S., long. 101° 16.8' W. 300 fms. to surface. 1 specimen. 



Sta. 4722. Jan. 16, 1905. Lat. 9° 31' S., long. 106° 30.5' W. 300 fms. to surface. 1 specimen. 



Sta. 4730. Jan. 20, 1905. Lat. 15° 7' S., long. 117° 1.2' W. 300 fms. to surface. 5 specimens (1 



among them very young). 



Sta. 4732. Jan. 21, 1905. Lat. 16° 32.5' S., long. 119° 50' W. 300 fms. to surface. 7 specimens. 



Sta. 4734. Jan. 22, 1905. Lat. 17° 36' S., long. 122° 35.6' W. 300 fms. to surface. 1 specimen, young. 



Sta. 4740. Feb. 11, 1905. Lat. 9° 2.1' S., long. 123° 20.1' W. 300 fms. to surface. 1 specimen. 



Description. — The frontal plate is produced, in the Pacific specimens fre- 

 quently nearly triangular, with the lateral margins feebly convex towards the 

 acute end (fig. la), but sometimes the margins are distally more convex and the 

 end broadly rounded, a little angular at the middle (fig. Ic); in specimens from 

 the North Atlantic the anterior part of the frontal plate is much broader with a 

 somewhat long and feebly curved transverse margin in front; on the end or 

 slightly behind the end of the frontal plate a minute vertical tooth — the re- 

 mainder of the rostrum in the young — is seen ; the plate is very thick and longi- 

 tudinally concave at the middle so that a pair of submedian keels are formed 

 uniting at the tooth mentioned, and a little or somewhat behind the tooth begins 

 in the bottom of the median excavation the median keel, which is rounded, 

 rather low, increases in height at the dorsal organ and disappears somewhat 

 before the place where the non-existent cervical groove is to be looked for; the 

 lateral edges of the frontal plate are bent a little upwards, so that the surface 

 becomes a little excavated along each margin. The carapace has a longitudinal 

 furrow close at the lateral margin almost from its anterior end, and posteriorly 

 this furrow is curved upwards along the lower half of the posterior margin; 

 the surface of the carapace without any other groove or impression; the pro- 

 duced part of the anterior margin above the antennae is a small, short, acute 

 triangle. 



The eyes are somewhat small, black. — The antennulae (figs, la-lb) are 

 very characteristic. The basal joint is somewhat short and very broad, with a 

 moderately short, spiniform process at the distal outer angle; the joint is dis- 

 tally strongly raised as an obliquely transverse, vaulted part with a number 



