ZOOTOMY 



THE LAMPREY. 



THE SEA LAMPREY (Petromyzon marinus). 

 THE FRESH-WATER LAMPREY, OR LAMPERN (P. fluviatilis). 



A. THE SKELETON. 



I. The preparation of the lamprey's skeleton is a very 

 laborious process, owing to the extreme toughness 

 of the connective tissue which invests it. Re- 

 moval of the latter is assisted by maceration in 

 nitric acid, 10 per cent, care being taken not to 

 allow the acid to act too long, the result of pro- 

 longed maceration being the entire separation of 

 the cartilages of the skull proper, and the total 

 destruction of the branchial basket. In preparing 

 a skeleton for demonstration purposes, it is, how- 

 ever, advantageous to allow the cartilages to se- 

 parate, and then to articulate them with fine 

 platinum wire. The branchial basket can then 

 be shown by itself in a special dissection. The 

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