'^%l''] proceedings of the national museum. 115 



seas, are the I'latyvephaiida', with 27 vercebra;, and the CephalacanthUJfCj 

 with bat 22. In the deeper waters of the tropics are the Peristediidm,, 

 with 33 vertebrte, and exteiidinj^ farther north, belonging as much to- 

 the temperate as to the torrid zone, is the hirge family of the Trigliilw,* 

 in which the vertebrre range from 25 to 38. 



The family of A(fonida',i with 'Si} to 40 vertebra', is still more decidedly 

 uorthern in its distribution. VVliolly contiued to northern waters is the 

 great family of the Cottida\\ m which the vertebrie ascend from 30 to 

 50. Entirely polar and often in deep waters are the Liparididw,^ im 

 offshoot from the Coifida\ with soft, limp bodies, and the vertebr;B 35' 

 to 05. In these northern Ibrms there are no scales, the spines in the tins 

 have ]nactically disappeared, and only the anatomy shows that they 

 belong to the group of spiny-rayed ti.shes. In the Cyclopteridw,\\ like- 

 wise largely arctic, the body becomes short and thick, the backbone 

 inflexible, ami the vertebra? are again reduced to 28. In most cases, as- 

 the number of vertebrae increases, the body becomes proportionally 

 elongate. As a result of this, the tishes of arctic waters are, for the 

 most part, loug and slender, and not a few of them approach the form' 

 of eels. In the tropics, however, while elongate fishes are common 

 enough, most of them (always excepting the eels) have the normal 

 number of vertebra*, the greater length being due to the elongation |f 

 of their individual vertebras and not to their increase in number. 



In the great group of blenny-like fishes the facts are equally striking. 

 The Arctic species are very slender in form as compared with the 

 troi)ical blennies, and this fact, caused by a great increase in the num- 

 ber of their vertebrie, has led to the separation of the group into sev- 

 eral families. The tropical forms composing the family of Blenniidcc** 

 have from 28 to 49 vertebra?, while in the Arctic genera the numbers 

 range from 75 to 100. 



The Anacanthine fishes in whole or in part seem to have sprung from 

 a Blenuioid stock. Of these the most specialized group is that of the 

 flounders, tt alread}^ described. The wide distribution of this family, its 



* Tlie gurnards and sea robuis. The lowest uuuibers are found iu tbe Aniericau 

 genus Prionotus, wliicli is chiefly tropical, tbe liigbest iu Lejiidotritjla, wbicb is confined 

 to soutbern Europe. 



t Sea poacbers, alligator bsbes, etc. t Sculpius, Miller's tbunibs, etc. 



'^ Sea snails. || Luuipfisbes. 



H Thus tbe very sleuder goby, Gohiiis oveaniciis. bas tbe same number (25) of vertebrae 

 as its tbick-set relative (iobiiis soporator ov tbe cbubby Lophoi/obiiis ciii)riii aides. 



*" Of tbe true Blenniida', wbicb are all tropical or semi-tropical, JjUiinius bas 28 to 

 35 vertebrie ; Salarias, 35 to 38 ; Labrosomus, 34 ; Clinus, 49 ; Cristiceps, 40. A fri\>-b- 

 water species of Cristiceps foiiud iu Australia bas 46. Blennioid fisbes in tbe Arctic 

 seas are Anarrhivhas, witb 76 vertebrie ; Aiiarrhickthys, witb 100 or more ; Lumpciius, 70 ; 

 Miownoides, 85; Lycodes, 112; Gymnelis, 93. Lycodes and Gymnelis have lost all the 

 dorsal spines and are intermediate between tbe blennies and the forms called Ana- 

 cantiiine. Tbe gradual degeneration of such northern forms may perhaps be attrib- 

 uted to tbe influence of "faumixia ' or the cessatioa of tjelectiou, 



ft Fleuronectida;, 



