Marine Copepoda 



15 k 



In one specimen the caudal furca was asymmetrical, suggesting a mingling 

 of characters, as shown in Fig. 13. 



The arrangement of the setae on the natatory legs agrees with that of E. 

 velox. except that the third joint of the outer branch of the first foot (p. 1 Re 3) 



Fig. 13. E . johanseni 6 . 

 Abnormal caudal fvirca. 



is furnished, as in E. herdmani, with seven setae (2 se, 1 st, 4 si); in E. velox 

 this joint has six setae (1 se, 1 st, 4 si). 



12. Metridia longa (Lubbock, 1854). 



Station 27r. Collinson Point, Alaska, October 2, 1913 : one male, with the 

 left anterior antenna geniculate; length 3-88 mm. 



Station 29g. 70° 20' N., 140° 30' W., depth 150 fathoms: several vertical 

 hauls with net number 5, from to 150 fathoms, April 6, 1914. The gathering, 

 amongst others (see under Calanus finmarchicus), contained females and young; 

 one female was 4-88 mm. in length. 



Station 42j/. See Table X. Young individuals. 



Station 42z. See under Pseudocalanus. A young Metridia longa of 1-67 

 mm. was taken. 



From these scanty records it is evident that this representatiye Arctic 

 species was only present in traces. Its abundance at suitable places in the north 

 is shown in the following extract, which I have not seen quoted before, 

 from A. E. Nordenskiold : The Voyage of the Vega round Asia and Europe, 

 translated by A. Leshe, London (Macmillan) 1881, vol. II, pp. 54-56: "The 

 common idea that all animal life ceases when the interior animal heat sinks 

 under the freezing point of water, is not quite correct. This is proved by the 

 remarkable observation made . . . during the wintering at Mussel Bay in 

 1872-73, that small Crustacea can live by millions in water-drenched snow at 

 a temperature of from — 2° to — 10° -2 C. If during winter one walks along the 

 beach on the snow which at ebb is dry, but at flood tide is more or less drenched 

 through by sea-water, there rises at every step one takes, an exceedingly intense, 

 beautiful, bluish-white flash of light, which in the spectroscope gives a one- 

 coloured labrador-blue spectrum. It produces indeed a peculiar impression on 

 a dark and stormy winter day (the temperature of the air was sometimes in 

 the neighbourhood of the freezing-point of mercury) to walk along in this 

 mixture of snow and flame. On a closer examination, it appeared that this 

 light-phenomenon proceeded from a minute crustacean, which, according to 

 the determination of Prof. W. Lilljeborg, belongs to the species Metridia armata 

 A. Boeck (= M. longa). When the temperature [of the snow-sludge] sinks 

 below — 10° C, the power of this small animal to emit light appears to cease." 



