W. S. MacLeay on the Natural Arrangement of Fishes. 197 



the Asterice as foraied of the union of numerous individuals 

 attached around a common mouth. In a notice on some 

 points of the organization of the Euryales (Mem. de la Soc. 

 des Sc. Nat. de Neuchatel, tom. ii.), I have given circumstan- 

 tial details of the structure and disposition of the solid parts 

 of these animals, and have described comparatively two new 

 species. 



Messrs. Sars and Forbes have reviewed what Otto Fr. 

 Miiller has said respecting the Pedicellarm of the Echino- 

 dermata, and have added some new observations upon these 

 singular bodies (Hist, of Brit. Starf, p. 155). 



[To be continued.] 



XXIV. — On the Natural Arrangement of Fishes. By W. S. 

 MacLeay, Esq., A.M., F.L.S., in a Letter to J. M'Clel- 

 land, Esq., dated Elizabeth Bay, near Sidney, N. S. W., 

 September 12th, 1840*. 



My Dear Sir, 

 I CANNOT find terms to express my gratitude for your kind letter of 

 the 12th March last, and for the very valuable present which it ac- 

 companied. 1 assure you, that your excellent work on Cyprinida 

 has afforded me the greatest delight, and the more so, inasmuch as I 

 am convinced natural arrangement is always best tested by accurate 

 analysis, and also inasmuch as 1 am not by any means satisfied with 

 Swainson's arrangement of Fishes. As from everything Swainson 

 writes there is information to be derived, so I assure you, his little 

 volume on Reptdes and Fishes has not been lost on me ; yet the per- 

 usal of 3^our ^lonograph on Indian Ci/prinidcef has made me recur to 

 my old views on a subject which our common friend Dr. Cantor 

 may have told you has long occupied my thought ; and although 

 perhaps you will deem these views not sufficiently worked out, and 

 rather crude, I cannot refrain from making you acquainted with 

 them, in order that I may have the benefit of comparing your ge- 

 neral arrangement of Fishes with my own . 



Fishes form a class of Vertebrata which has never yet been satis- 

 factorily divided into orders. I do not tliink that Acaathopterygii and 

 Malacopterygii, for instance, are natural orders. In order therefore 

 to arrive at the first great and natural division of Fishes, I think we 

 must commence by incontestable data, or at least by facts that are 

 generally agreed on. Such facts, for instance, I hold to ])e the three 

 following, A'iz. 1. The near approach of fishes to Batrachian Am- 

 phibia, which with Swainson I consider to be made by means of Lo- 

 phius and Mcdthe. 2ndly. The near approach of fishes to Cetaceous 

 Mammaha, which with him also I consider to take place by means 

 of Selache and the viviparous Sharks. 3rdly. As the grand character 

 of fishes as a class is, their being the most imperfect of Vertebrata, 



* From the Calcutta Journal of Nat. Hist, for July 1811. 

 t See Ann. and Mag. Nat. Hist., vol, viii. p. '^^. 



