120 THE FAUNA OF THE DEEP SEA 



sentative species in the abyss ; but, with the exception 

 of a want of brilliant coloration and marking and a 

 thinness of the shell, the deep-sea forms do not exhibit 

 any characteristic features. One of the most brightly 

 coloured shells found at great depths is that ofScala/ria 

 mirifica, which is tinted rose and white, but this 

 seems to be quite an exceptional character among 

 the deep-sea Gasteropods. Several new genera were 

 found in the deep water, but their general characters 

 do not call for any special remark. 



Among the Cephalopoda there seems to be little 

 doubt that the genera Cirroteuthis, Bathyteuthis, 

 and Mastigoteuthis are entirely abysmal, and the same 

 applies probably to one or two species of octopus ; but 

 as Hoyle remarks, * apart from the single fact that 

 Bathyteuthis and Mastigoteuthis both have slender 

 filiform tentacles with minute suckers, no structural 

 features have been discovered which will serve to 

 diagnose a deep-sea form from a shallow-water one.' 



The exact habitat of the interesting genus Spirula 

 is unfortunately still unknown. In some parts of 

 the tropics the shores are covered with spirula shells, 

 and yet the animals that secrete them are still to 

 be reckoned amongst the greatest rarities of our 

 museums. The numerous dredgings of the ' Chal- 



