the medium of the lists of double numbers, written fair in a 

 separate volume by Mr. Clift. 



A sixth document, of much importance in the identification 

 of the individual specimens, is a manuscript catalogue, by Mr. 

 Hunter, of a series of drawings, chiefly taken from preparations 

 in the Museum, and intended to illustrate their description. 

 About thirty specimens, in some instances of complicated and 

 minute structures, have been determined by this mode of com- 

 parison. 



The original Hunteriau descriptions have been retained, as 

 far as possible, in the present catalogue ; additions have been 

 made to them, when they were found not sufficiently clear ; and 

 new descriptions have been given of all the remaining prepa- 

 rations. 



The information most commonly required in addition to the 

 previous descriptions and notices, has been the name of the 

 species of plant or animal from which the preparation had been 

 derived. 



Where this information is attempted to be given in the manu- 

 script catalogues the reference is commonly to the genus or to 

 some still wider group of animals, as ' a monkey/ ' a whale/ ' a 

 beetle/ ' a snail ; ' or the indication is still more vague, as ' an 

 insect/ ' a sea-worm/ ' a shell-fish/ &c. In a great proportion 

 of the specimens the description relates only to the organ, or 

 ends with ' animal unknown/ In many cases, where the species 

 is more definitely indicated in the folio catalogue, rectification of 

 the name has been found necessary, as will be seen by whoever 

 may compare the present catalogue with that document. The 

 mistakes which have hitherto been detected, have arisen from 

 placing confidence in the statements as to the species of animal 

 contained in the manuscript documents, before experience of 

 their occasional fallacy had shown the necessity of testing them 

 by a dissection of the animal to which a preparation was so 

 referred, or by a comparison of the preparation with such 

 descriptions and figures of the anatomy of the same animal as 

 could be found in print. 



It is impossible to reason correctly upon the structure of a 



