43 

 3. Chiridius ? obtusifrons Sars. Plate XLIV, figs. i — 3. 



Chiridius armatus Sars (non Boeck) 1900, p. 64, pi. XVII. 



Chiridius obtusifrons Sars, 1902, p. 29, pi. XVII. 

 Chiridius obtusifrons van Breemen, 1908, p. 34, fig. 37. 



A single specimen that I ara inclined to regard as identical with Sars' Chiridius 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 Chiridius poppci. The exopodite 

 of the second, third, and fourth pairs of swimming feet in the 'Siboga' specimen, is distinctly 

 three-jointed as in the other Chiridius 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 cepJialo- 

 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 Euchirella and Uudeuchaeta. 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. Esterlv. 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 streetsi Giesbrecht. Plate XII, figs. 1 — 11. 



Chirundina streetsii Giesbrecht, 1895, p. 250, pi. I, figs. 5 — 10. 

 Chirundina streetsi Giesbrecht & Schmeil, 1898, p. 34. 

 Euchirella carinata Wolfenden, 1902, p. 366. 

 Euchirella carinata Wolfenden, 1904, p. 115. 



Chirundina streetsi 

 Chirundina streetsi 

 Chirundina streetsi 

 Chirundina streetsi 

 Chirundina streetsi 



Cleve, 1904, p. 187. 



Sars, 1905 (a), p. 4. 



Esterly, 1906, p. 59, pis. 9, 10, 12, 14. 



Pearson, 1906, p. 16. 



Farran, 1908, p. 37. 



Chirundina streetsi van Breemen, 1908, p. 46. 



Chirundina streetsi appears to be a moderately deep water form, and was found in 

 several of the vertical net hauls, as shewn by the records. 



43 



