43 
3. Chiridius ? obtustfrons Sars. Plate XLIV, figs. 1—3. 
Chiridius armatus Sars (non Boeck) 1900, p. 64, pl. XVII. 
Chiridius obtustfrons Sars, 1902, p. 29, pl. XVII. 
Cliridius obtusifrons van Breemen, 1908, p. 34, fig. 37. 
A single specimen that I am inclined to regard as identical with Sars’ Cherzdzus obtu- 
sifrons, was found in the plankton taken in a HENSEN vertical net haul at Station 141, 1500 
metres to surface. 
_ The specimen differs, however in the following details: — The length is 2,6 mm. and the 
various appendages are the same as in the species identified as Chzrzdius popper. The exopodite 
of the second, third, and fourth pairs of swimming feet in the ‘Siboga’ specimen, is distinctly 
three-jointed as in the other Chzrzdzus illustrated in this report. The combined length of the 
abdomen and furca, is contained about two and a half times in the total length of the cephalo- 
thorax, from the frontal margin to the base of the genital segment. 
The very short spines of the last thoracic segment although not divergent, appear to 
agree very well with the figure given by Sars, and this is the chief reason for supposing, that 
the specimen may only be a tropical variation of the type from the Coast of Norway. 
Genus Chirundina Giesbrecht, 1895. 
The female of this genus is allied to LEuchirella and Undeuchaeta. The rostrum is 
moderately long and one pointed. The forehead has a distinct crest. The last thoracic segment 
is produced on each side into a small knob. The exopodite of the first pair of swimming feet 
is indistinctly three-jointed, and the inner margin of the first joint of the basiopodite of the 
fourth feet is without spines. The fifth pair of feet is absent. 
The male was described and partly figured for the first time by C. O. Esrrerty. It differs 
from the female in the last thoracic segment not being produced into knobs. The abdomen is 
composed of five joints. The exopodite of the first pair of feet is distinctly three-jointed, and 
there is a well developed prehensile fifth pair of feet. 
Only one species is known. It was well represented in the plankton collected by the ‘Siboga’. 
1. Chirundina streetse Giesbrecht. Plate XII, figs. 1—11. 
Chirundina streetsiz Giesbrecht, 1895, p. 250, pl. I, figs. 5—1IO0. 
Chirundina streetst Giesbrecht & Schmeil, 1898, p. 34. 
Euchirella carinata Wolfenden, 1902, p. 366. 
Euchirella carinata Wolfenden, 1904, p. 115. 
Chirundina streetst Cleve, 1904, p. 187. 
Chirundina streetst Sars, 1905(a), p. 4. 
Chirundina streetse Esterly, 1906, p. 59, pls. 9, 10, 12, 14. 
Chirundina streetst Pearson, 1906, p. 16. 
Chirundina streetst Farran, 1908, p. 37. 
Chirundina streets: van Breemen, 1908, p. 46. 
: Chirundina streets’ appears to be a moderately deep water form, and was found in 
several of the vertical net hauls, as shewn by the records. 
43 
