271 



of two lively examples has enabled me to supply some account 

 of the beautiful respiratory plume, which, however, scarcely 

 differs from that of P. membranaceus ; it proceeds from the 

 anterior part of the right side, and lies in the groove of the 

 disks. It consists of a gently arcuated stem, having on each 

 side 20-25 oblique rami sloping posteriorly, which are finely 

 ciliated, to beat the water to extract the air; the two sets of 

 strands fall together from each side of the stem, forming when 

 expanded an elegant plumose rouleau, tapering gently from its 

 origin to a conical though obtuse posterior termination, and 

 for a third of its length floating free. 



APLYSIAD.E. 



This most ancient and celebrated family, from the fabulous 

 incidents that have for so many ages been attributed to it, 

 has received a greater share of attention from the learned of all 

 countries than any other mollusc. This harmless creature, 

 like the inoffensive Toad, has immemorially been loathed aiid 

 buffeted, not only by every ignorant rustic, but by the thought- 

 less of superior grade ; more evils than ever issued from Pan- 

 dora's box have been laid to its charge; it has had the 

 character of being the ready agent of every sorceress and 

 practised Canidia, to rid the world of fathers who have lived 

 too long, and avenge the deadly offences of the lusts and 

 passions. The distinguished zoologists of every nation and 

 age have described its external and internal configuration ; I 

 need only mention the elaborate anatomies of Baron Cuvier, 

 M. De Blainville, and M. De Ferussac ; it would therefore be 

 supererogatory and almost presumptuous to meddle with that 

 which has received the investigations of such distinguished 

 naturalists ; we use a wise discretion in only referring to their 

 labours, and particularly to the memoir of M. Cuvier ; this 

 eminent man must always be regarded as a model of singular 

 fidelity combined with admirable descriptive simplicity. 



There is only one well-authenticated British species, the 



