102 LECTURE IX. 



colours and the pure, glassy, transparency of their tissues, which 

 baffle all his arts of preservation, and can never be displayed in the 

 cabinet. They often leave upon the unwary hand of the captor pun- 

 gent evidence of their singular power of inflaming the skin. It is this 

 stinging or urticating property which has procured for the " Radi- 

 ares Mollasses" of Lamarck the name of AcalephcE amongst the 

 ancient Greek naturalists, and " Sea nettles " from our own fisher- 

 men and sailors. 



The Acalephce are represented on the British coasts by numerous 

 discoid and spheroid gelatinous animals, varying in size from an 

 almost invisible speck to a yard in diameter, known by the name of 

 " Sea blubber," " Jelly fish," or by the Linnaean generic term 

 " Medusar 



Occasionally some of the singular forms of Acalephce of the tropical 

 seas are stranded on the south-western shores of England. I have 

 picked up on the coast of Cornwall the little Velella, which had 

 been wafted thither, unable to strike its characteristic lateen-sail. 

 There also I have seen wrecked a fleet of the Portuguese men-of-war 

 (JPhysalia), which had been buoyed by their air-bladders to that 

 iron-bound coast. 



The most characteristic features in the organisation of the Aca- 

 lephae, may be exemplified by the anatomy of the larger Medusce of 

 our own seas. 



The first thing which astonishes us in commencing the dissection 

 of these creatures is the apparent homogeneity of their frail gelatinous 

 tissue; secondly, the very large proportion of the body, which seems to 

 consist of sea water, or a fluid very analogous to it : for let this fluid 

 part of a large Medusa, which may weigh two pounds when recently 

 removed from the sea, drain from the solid parts of the body, and 

 these, when dried, will be represented by a thin film of membrane, 

 not exceeding thirty grains in weight. The art of the anatomist would 

 seem to be baffled by the very simplicity of his subject, instead of, as 

 in other cases, by the inability to pursue and unravel all the intricate 

 combinations of the created mechanism. Peron and Lesueur, two 

 experienced French naturalists, who, during the circumnavigatory 

 voyage to which they were attached, paid great attention to the 

 floating Acalephce^ have thus summed up the results of their ex- 

 perience in regard to their organisation. " The substance of a 

 Medusa is wholly resolved, by a kind of instantaneous fusion, into a 

 fluid analogous to sea water ; and yet the most important functions 

 of life are efi'ected in bodies that seem to be nothing more than, as it 

 were, coagulated water. The multiplication of these animals is pro- 

 digious; and we know nothing certain respecting their mode of 



