1320 THE STORY OF THE UNIVERSE 



while one family type, the Echinothuridae, has been 

 hitherto only known in a fossil state, the entire 

 group finds nearer allies in the extinct faunae of the 

 chalk or of the earlier Tertiaries than in that of 

 the present period. 



Many of the mollusca from the deep water have 

 hitherto been found only in the northern portions of 

 the area examined, and are generally allied to north- 

 ern forms. 



The abyssal mollusca are by no means devoid of 

 color, though, as a rule, they are paler than those 

 from shallow water. Neither are the abyssal mol- 

 lusca universally destitute of eyes. A new species 

 of Pleurotoma from 2,090 fathoms had a pair of 

 well-developed eyes on short footstalks ; and a Fusus 

 from 1,207 fathoms was similarly provided. The 

 presence of organs of sight at these great depths 

 leaves little room to doubt that light must reach even 

 these abysses from some source. From many con- 

 siderations it can scarcely be sunlight. The whole 

 of the light beyond a certain depth might be due 

 to phosphorescence, which is certainly very general, 

 particularly among the larvae and young of deep- 

 sea animals. 



"THE MIMIC FIRES OF OCEAN" 

 G. CLARKE NUTTALL 



NATURE dazzles the eye of man with many 

 wonderful phenomena, but perhaps never 

 more so than when she turns the gloomy night waters 

 of the sea into a sheet of silvery fire. At these times 



