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XVIII. — The Chaetognatha of the Scottish National Antarctic Expedition of 1902- 

 1904. By A. Pringle Jameson, B.Sc. Communicated by Dr W. S. Bruce. 



(MS. received June 21, 1913. Read July 21, 1913. Issued separately February 24, 1914.) 



A considerable number of Chaetognatha were collected on the Scottish National 

 Antarctic Expedition of 1902-1904. Some two or three hundred tow-nettings were 

 examined, and about ninety yielded some of these forms. Beside the tow-netting 

 samples there were twelve tubes of these animals taken in the vertical net or 

 the trawl. 



It will thus be seen that most of the material consists of tow- nettings which, 

 almost without exception, were taken at the surface of the water. If we accept 

 Dr Bruce's definition of the Antarctic Regions,"^ namely, the area to the south of the 

 average limit of floating ice according to the British Admiralty Ice Chart, No. 1241 

 {vide text-map), we may expect Antarctic forms there. Chaetognatha were taken by 

 the Scotia at ten stations south of this line, including only four out of the many 

 surface tow-nettings taken by the Scotia south of this line, whilst a fifth, although 

 taken in latitude 39° 48' S, (Station 468), is in close proximity to it, and actually 

 within the extreme limit of floating ice. The ten stations are Nos. 273, 280, 325, 346, 

 398, 414, 416, 422, 448, 450, and besides the eleventh above mentioned, viz. 468. 



The Antarctic species are : — 



1. Sagitta gazellse (Ritter-Zahony). 



2. Sagitta m,axim,a (Conant). 



3. Sagitta 'planctonis (Stein ha us). 



4. Eukrohnia hamata (Mobius). 



5. Heterohrohnia sp. ? (Ritter-Zahony). 



The catches of the vertical net and the trawl were, with one exception — namely, the 

 trawling made on April 29, 1904, in 39° 48' S., 2° 33' E.— taken south of 40° S. and 

 south of the average limit of floating ice. Thus this one catch is hardly an exception, 

 so that practically we may say all these catches belong to the Antarctic series. All the 

 other Chaetognatha captured were taken north of this line as far north as 36° N. latitude. 



The tropical and sub-tropical species are : — 



1. Sagitta hexaptera (d'Orbigny). 



2. Sagitta enjlata (G-rassi). 



3. Sagitta serratodentata (Krohn). 



4. Sagitta hipunctata (Quoy and Gaimard). 



5. Sagitta rohusta (Doncaster). 



6. Pterosagitta draco (Krohn). 



7. Krohnitta, suhtilis (Grassi). 



* " Antarctic Birds," by William S. Bruce, Knowledge, September 1, 1894, p. 208. 

 TRANS. ROY. SOC. EDIN., VOL. XLIX. PART IV. (NO. 18). . 134 



