60 



KR. BONNEVIE. 



[rep. of the^'michael sars" north 



Fig. 51. Horizontal distribution of Clione limacina from the 

 "Michael Sars" expedition. 



The visceral mass does not fill the posterior part 

 of the body. a 



This species is so well known that a further discrip- 

 tion of its characters is unnecessary. In fig. 59 — 60, pi. 

 VIII, a specimen with fully extended penis and 

 buccal cones is shown. 



Geographical distribution. Aboutl20 

 individuals of this species were taken during 

 the "Michael Sars" expedition, nearly every 

 station along the northern crossing of the 

 ocean and a few stations along the southern 

 crossing, as far south as lat. 34° 44' N. (Station 

 64), being represented. 



Clione limacina is known as one of the 

 most characteristic representatives of the arctic 

 (and antarctic) fauna, and when met with on 

 warmer latitudes it has generally been con- 

 sidered an indicator of the presence of cold 

 water currents. Damas and Koefoed (1905) 

 maintained, however, that this did not hold 

 good in all cases, and that probably other fac- 

 tors play an important role in the distribution 

 of pelagic species. Among such factors light 

 was regarded as one of the most important, 

 leading to the occurrence of Clione near the 

 surface within the arctic regions, and in deeper 

 water in more southern latitudes. 



The distribution of Clione limacina as found 

 by the "Michael Sars" expedition during the 

 double crossing of the Northern Atlantic seems 

 however to indicate a very intimate connection 

 between the temperature and salinity of the 

 water on the one hand and the occurrence of 

 Clione on the other. 



As shown in the table this species was 

 taken during the northern crossing at a great 

 number of stations not only in the open ocean 

 (St. 81—92) but also, as the only representative 

 of pteropods, on the Newfoundland banks~(St. 

 71—80). Although the effect of the sunlight 

 would be practically the same at all these 

 stations, Clione limacina was found in the open 

 ocean, where the surface-layers are relatively 

 warm and salt, to belong to the deeper waters, 

 while it was taken near the surface of the cold 

 Labrador current. Also during the southern 

 crossing (Stations 64 — 75) Clione limacina was 

 found to belong to a water-layer with a tempe- 

 rature as low as from 4° to 10°C. 



Paraclione Tesch. 



Radula: Free border of the median tooth forming 

 long, pointed denticle (Formula: 3—1 — 3). 

 2 pairs of buccal cones. 

 Not represented in the "Michael Sars" collections. 



St. 



64 



66 



67 



70 



71 



75 



76 



80 



81 



Date 



2, h 



26 /s 



2 Vs 



9 % 



30 / 6 



*h 



. B ,7 



i./ 7 



12 /7 



N 

 Position w 



34° 44' 



39° 30' 



40° 17' 



42° 59' 



43° 18' 



47° 22' 



47° 11' 



47° 34' 



48° 2' 



47° 52' 



49° 42' 



50° 39' 



51° 15' 



51° 17' 



49° 16' 



47° 6' 



43° 1 1' 



39° 55' 



Depth in m. 

 0— 50 

 50— 100 













1 



1 



















— 



14 







— 







100— 250 



— 



1 



1 



4 













250- 500 



— 



2 



— 



1 



— 



— 



— 



1 



— 



500— 750 



— 



22 



2 



— 



— 



— 



— 



12 



— 



750-1000 



— 



11 



— 



— 



— 



— 



— 



— 



— 



1000—1250 



2 



















1250—1500 

















1 



1 





St. 



82 



84 



87 



88 



90 



92 



96 



98 



Date 



13/, 



15/, 



17 /7 



18/, 



21/, 



23/,_24/ ? 



27 /? 



5 / 8 



Position ^V 



48° 21' 



48° 4' 



46° 48' 



45° 26' 



46° 58' 



48° 29' 



50° 57' 



£6° 33' 



36° 53' 



32° 25' 



27° 46' 



25° 45' 



19° 6' 



13° 55' 



10° 46' 



9° 30' 



Depth in m. 



















0— 50 



















50— 100 















3 



— 



100— 250 



















250— 500 



















500— 750 

















14 



750—1000 



3 



3 



3 



2 



1 



— 



— 



— 



1000—1250 



— 



3 



3 



— 



— . 



3 



— 



— 



1250—1500 



1 



3 



— 



— 



— 



— 



— 



— 



Number of individuals of Clione limacina. 



