Connection and Locomotto?i. 529 



And mounted up and glided down the billow 

 In happy freedom, pleased to feel the air. 

 And wander in the luxury of light." * 



Such is the uniform account handed down to us by natu- 

 ralists and poets from a very early period ; nor need you 

 scruple to adopt the wonderful tale. It is true that " there 

 are not wanting plain matter-of-fact naturalists who deny that 

 the animal sails at all f ; " but this unbelief savours of over- 

 scepticism, or has perhaps no better foundation than a verbal 

 quibble. The story is told by several, who appear to have 

 been eye-witnesses of the fact J, and it is, in every particular, 

 conformable to the structure of the creature. It has six ten- 

 tacula tapered to a point, and it has two with a dilated mem- 

 brane at their tips ; and does it seem improbable, as authors 

 tell us, that these are held in different attitudes, and are fitted 

 for different purposes, while the cuttle pursues its vagrant 

 course ? Literally, though the contrary has not been proved, 

 the breeze may not fill the sails and become the moving 

 power ; yet to say that the parasite of the Argonauta sails is 

 scarcely speaking in a metaphor. 



The Heteropode and Pteropode Mollusca are likewise all 

 denizens of the ocean, in whose wide waters they move by 

 swimming, or by calmly floating with the current. They 

 have no foot wherewith to creep, and they have no arms to 

 drag themselves. The former are furnished with fins, variable 

 in number and position according to the species ; in the latter 

 they are always two, one being situated on each side of the 

 head. By an undulatory or flapping motion of these organs, 

 they move on at a slow rate, and in a reversed position, some 

 in their progress alternately dipping below, and reascending to 

 the surface. The whole of them, indeed, it is probable, are 

 capable of varying the specific gravity of the body at pleasure, 

 so as to rise or sink in the water as circumstances may require. 

 In calm weather, they will frequently ascend and float on the 

 surface in immense shoals, as is the case with the Clio borealis 

 and Limacina helicialis of the Arctic seas ; little snails which 

 I should have introduced to your notice earlier, as furnishing 

 the whale a great part of its sustenance. In swimming, 

 according to the intelligent navigator Scoresby, the Clio 



Montgomery's Pelican Island, canto i. 



+ Zool. Journal, iv. 58. 



In his Account of an Expedition to Surinam (vol. i. p. 11.), Stedman has 

 given a description of the Argonauta, concerning the accuracy of which I 

 would wish to warn the reader. He seems to have observed the Ho\o- 

 thiiria Physalis (which is not a molluscous animal), and mixed up the de- 

 scription of it with wliat he had read or heard of the Argonauta. 



