134 GENUS PLANES. 



Fucus vagans, or attached to the bodies of the large 

 marine turtles. The figures of Linnaeus in his " Iter 

 Wcstrocr." of Bowdich in the " Excursions in Madeira 



O 



and Porto Santo," the descriptions of Say, of Edwards, of 

 Mac Leay, and others, only tend to show that there are 

 several species in existence, but do not diminish the diffi- 

 culty of distinguishing them. It is not intended on this 

 occasion to attempt their discrimination ; but it would 

 be very desirable that the task should be undertaken by 

 some one having the means at hand of comparing a great 

 number of specimens. There is a good collection of them 

 in the British Museum, and I have little doubt that I 

 possess three species in my own collection. 



I have thought it right to restore the generic name of 

 Planes to these Gmpsida, because it was not only applied 

 to them by Leach in his MSS. in the British Museum, 

 but adopted by Bowdich in his book above referred to. 

 Whether Leach had ever published any account of the 

 genus under the name Planes or not, I have not been able 

 to ascertain ; but it is highly probable that Bowdich 

 quoted it from some such authority. 



