Mainmals, Birds, and Iloptiles, wliich breathe prineipallv tliroujrh 

 the nose ; the nostrils in Fishes, however, do not commnnicate 

 witli tlie breathinj; organs. 



At the head of the Fishes stand the Cartilaj^inous Fishes. 

 Their forms are familiarly known as the Sharks, including the 

 Dog Fishes, and the Rays, including the Skates. 



The smaller species of the Sharks, which are very numerous on 

 our coasts, have not yet survived in this aquarium, but I do not 

 doubt that the difficulty will be ultimately overcome. 



As to the larger species, it would require a ver}' large aquarium 

 for them. The Basking Shark, by no means rare in the British 

 waters, as many as sixty having been seen at one time, attains to 

 the enormous weight of six tons. 



]\Ir. Yarrell saw one at Brighton which measured thirty-six 

 feet in length. 



But to return to this aquarium. The Cartilaginous Fishes are 

 here represented by the Angel Fish, a kind of flat Shark, and by 

 the Skates. Both these thrive well, and the latter appear very 

 lively. 



The Skates are true flat fish ; both the eyes are above, and are 

 placed symmetrically in the head. The homologues of the fore- 

 legs in the higher vertebrates are here modified into broad expan- 

 sions on each side of the body, and are waved by the will of the 

 animal. The two claspers which you will see them moving when 

 endeavouring to climb the glass front of the tanks are the homo- 

 logues of the hinder feet of the Reptiles and Mammals. 



I think none of us who had seen only the repulsive looking 

 Skates as they appear at the fishmongers, could have formed any 

 idea of their graceful movements as here seen. 



Most of the Fishes in the aquarium belong to the second 

 division or sub-class of Fishes, the Osseous Fishes. These are 

 divided into two great divisions or orders, the Spine-finned — the 

 Perch is an example — and the Soft-finned, of which the Cod is an 

 illustration. There ai-e also two other smaller orders of Osseous 

 Fishes, the Plated-mouthed Plectognathi ; the Sun Fish is a fine 

 cxam])le, Avhich looks rather like the ghost of a Cod's head and 

 shoulders. 



The remaining order is the Tufted-gilled Lophobranchii. The 

 strange form of the Fishes composing this order is well shewn in 

 the Hippocampus, or Sea Horse. 



The shai)c of the scales in Osseous Fishes also forms a good 



