VI INTRODUCTION. 



fluous in the eyes of tlie experienced naturalist, Avill serve to give the 

 creneral ideas intended for the use of others, and to facilitate the reference 

 of the Madeiran fishes to their respective families or groups. 



Be it assumed then, and merely on the quite sufficient principle, " Si 

 non rogas, intelligo,"'"' that it is known with somewhat more than popular, 

 though not with scientific accuracy, what constitutes distinctively a fish. 

 I mean, that although a person may not be able to give technically a 

 precise or abstract verbal definition of the tribe, he yet, by reference to 

 their vertical instead of horizontal tail, — their breathing water, instead 

 of air immediately, by means of gills, not lungs, — and to their generally 

 laying spawai or eggs, which they desert, instead of always bringing forth 

 their young alive and subsequently suckling them, — shall be able to dis- 

 tinguish any of the families of fishes from the mammiferous, phocaceous, 

 or cetaceous tribes of Seals, Whales, Dolphin, Grampus, Porpesse, Dugong, 

 Manati, &C. One door to error is thus closed. Again, and on the other 

 hand, he is supposed to knoAv that the presence of a vertebral or spinal 

 column, excludes a vast mass of other co-inhabitants of the water ; which 

 are primarily distinguished by the absence of this bone, and therefore 

 called the Invertehraia. Such are all Shell-fish, Lobsters, Crabs, Shrimps, 

 Mollusks, Cuttle-fish, Jelly-fish, Star-fish, AVorms, Polypi, &c. 



There still remains a large residue of well-known striking animals, con- 

 sisting of the Sharks, the Skates or Rays, the Sturgeons, Lampreys, Sun- 

 fishes or Globe-fishes, and Pipe-fishes, blended with the true fishes ; of 

 which they form collateral and aberrant, or more or less anormal groups : 

 being externally, by form and habits, and internally, by structure and 

 organization, more nearly related to these, than to any other tribe of 

 animals. It must, however, be remembered, that they form of these, in 

 general, co-ordinate or collateral, not subordinate or essentially inferior 

 groups : the organization of some, e. g. the Sharks and Rays, tending 

 evidently towards the structure of the higher animals, through the class 

 of Reptiles ; whilst that of the Lampreys, on the other hand, approaches 

 downwards towards the Worms, i. e. towards the higher JNIollusks, or 

 Cephalopoda. 



These groups then constitute, in scientific phraseology, the families 

 Sj/ngnathida, Pipe-fishes and Hippocampuses; Diodontido' and Balistida, 

 Sun-fishes, and File-fishes ; Sturionidtt, Sturgeons ; Sqiialidtr, Sharks ; 

 Raiid.T, Skates and Rays ; and Petromijzidfe, Lampreys. They are placed 

 by Cuvier at the end of the more obvious or true fishes. The two former 

 compose, respectively, the last two orders of the six into which he divides 

 his first series, or " Poissons ordinaires." The four latter arc united 

 together, under the name of Chondropterygiantt!, in allusion to their 

 common character of cartilaginous (/ovSpoc) instead of fibrous bones or 



