22 THE NATURAL HISTORY REVIEW. 



jugular es of the old autliors) appear to Dr. Gunther to be a very 

 natural order, although the want of symmetry in the Pleuroneetidse 

 would at first sight induce one to distinguish them rather strongly 

 from the symmetrical Gradidae and their allies. But, as Dr. Giinther 

 reminds us, the absence of symmetry in the latter is the only 

 constant character upon which such a distinction can be made, and 

 in the more highly organized Pleuronectidse (such as Fsettodes) 

 this character is but little developed. On the other hand the 

 Gadidas and Pleuronectidse agree in other important characters, 

 such as the great development of the dorsal and anal fins, the 

 position of the ventrals, and the increased number of the caudal 

 vertebra?. 



Dr. Giinther gives 1090 species of Acanthopterygii Pharyn- 

 gognathi and Anacanthini, of which he considers 890 to be well 

 characterized. There are a great number of new species described 

 in these two orders, particularly in the families Chromidse and 

 Pleuronectidse. In the former groups the freshwater lakes of 

 Guatemala, lately explored for the first time by Messrs. Salvin and 

 Godman, have yielded an abundant harvest, and we believe a 

 special communication of Dr. Giinther on this subject, with figures of 

 many of the new species, will shortly appear in the Zoological 

 Society's " Transactions." 



Dr. Giinther's fifth volume commences the series of those families 

 of Pishes, which Miiller called Fhysostomi, from the air bladder being 

 connected with the pharynx by an air-duct. The extensive family of 

 8iluroids is taken first, of which nearly 700 species are known, and 

 the details of which take up the greater portion of the volume. These 

 are followed by the Characinoids and several other smaller families. 

 Amongst these perhaps the most noticeable in the way of novelty is a 

 new genus of Australian freshwater fish called Frototroctes — the 

 representative of the Salmonoids of the K'ortheru Hemisphere in 

 the Antipodes. The genus is of greater interest as being naturally 

 associated in one family with the genus Ilaplocliiton of Jenyns, 

 discovered by Mr. Darwin, during the voyage of the Beagle, in the 

 freshwaters of the temperate parts of South America, and thus givino- 

 us a new link between the Pauna of Australia and that of South 

 America, 



Dr. GUnther's fifth volume is also of great importance in making 

 such extensive additions to our knowledge of the fishes of the Kile 

 basin— the Silurida? and Characini, being as is well known very fully 



