332 M. Agassiz on Fishes. 



Sparoides, Scor pendicles, and Auloslomes. There are the Anthop- 

 terigians of Cuvier and Artedi, with exception, however, of those 

 having smooth scales, and with the addition of the Pleuronectes. 



Order IV. Cycloides. — The families belonging to this order are 

 provided with scales formed of simple laminae with smooth edges, a 

 circumstance which does not prevent their external surface being 

 frequently ornamented with different designs, which are imprinted 

 on all the laminae, where they are exposed to view and are not co- 

 vered over. The scales of the lateral line are formed like all the 

 others ; but, in place of being mere laminated plates, these are fun- 

 nels, placed the one within the other, and of which the narrow part, 

 applied to the disc of the scale, forms a tube, from which the mucus 

 which covers the fish is poured out. This tube is sometimes bifur- 

 cated or even ramified. In this order are placed the Labroides, 

 Muges, Atherines, Scomberoides, Gadoides, Gobioides, Murenoides, 

 Lucioides, Salmones, dupes, and Cyprinidoe. 



If we estimate the number of species of fishes, now known to 

 amount to about 8000, we may state that more than three- 

 fourths of this number belong to two only of the above-men- 

 tioned orders, namely Cycloides and Ctenoides, whose presence 

 has not been discovered in the rock formations below chalk. 

 The other fourth part of living species is referable to the or- 

 ders Placoides and Ganoides, which are now far from numerous, 

 but which existed during the whole period which elapsed since 

 the earth began to be inhabited, to the time when the animals 

 of the greensand lived. The remarkable conclusion to which 

 M. Agassiz had come from the study of more than 600 fossil 

 fishes on the Continent, has been corroborated by the inspec- 

 tion of more than 250 new species, found in the British collec- 

 tions. 



In the first, second, and third numbers there are descriptions 

 and admirable figures of genera and species of the different or- 

 ders, both Continental and British. General discussions also 

 occur ; one in particular we recommend to the attention of our 

 readers, viz. that on the colours and scales of fishes. 



The fourth number contains a critical review of the numerous 

 tribes of fossil fishes found in the famous Monte Bolca, and a 

 tabular view of the fishes of the chalk formation. M. Agassiz, 

 ki the same number, informs us that he obtained vast additions 

 to his former stores in the British collections, of which the fol- 

 lowing are noticed : viz. British Museum, Museum of the Geo- 

 logical Society of London, of the College of Surgeons, and of 



