407 



Annals and Magazine of Natural History. Vol. 2, No. 8, lor August, 1858. 

 London. From the Courtis Fund. 



Encj'clopajdia Britannica. Vol. XVI. 



Memoirs of the Life of John Quincy Adams. By Josiah Quincy, LL. D. 

 8vo. Boston, 1S58. Deposited by the Ripiiblican Institution. 



October 6, 1858. 



Dr. C. T. Jackson in the Chair. 



Prof. Agassiz, as an introduction to the description of 

 some new fishes from Lake Nicaragua, made some 

 remarks on classification. 



He observed that as yet there is no natural ichtliyological sys- 

 tem. The three principal ones which have attracted the attention 

 of naturalists are the following, in chronological order. 1. That 

 of Cuvier, remarkable for its precise divisions into natural fami- 

 lies, founded on the consistence of the skeleton, and on the char- 

 acters and situations of the fins. 2. His own system, based on 

 the structure of the scales ; this, though placing too great stress 

 on external characters, led to the discovery of many interesting 

 affinities between the scales and the internal organs. 3. That of 

 Johannes Miiller, deriving the characters from purely anatomical 

 Structure, leading to combinations without regard to zoological 

 differences. The fault of all these systems is their exclusiveness, 

 attaching too great value to single characters. He thought a 

 combination of the three systems would lead to a better appre- 

 ciation of certain groups. The Nicaraguan fishes, collected by 

 Julius Fi-oebel, are representatives of four genera of a single 

 family, foreign to North America ; though much resembling 

 Pomotis, they belong to the family of Chromids. 



In the family of Labroids, in which the Chromids were for- 

 merly included, the last pharyngeal bones are united into a single 

 odd bone, without trace of suture — there is no fissure between the 

 fourth and fifth branchial arches ; the last gill is imperfectly de- 



