^°iVl!' ] PROCEEDINGS OF THE NATIONAL MUSEUM. 113 



the general rule for wliicli there i« no evident reason unless it be con- 

 nected witli the wide distrilnition of these almost cosmopolitan fishes. 



In a fossil herring-like tish from the Green liiver shales, 1 count 40 

 vertebrit ; in a bass like or serranoid tish from the same locality -4, 

 these being the usual numbers in the present tropical members of these, 

 groups. 



The great family of Siliiridw or cattishes seems to be not allied to the 

 Isosjxfudyli, but a separate oftshoot from another ganoid type. This 

 groui) is represented in all the fresh waters of temperate and tropical 

 America, as well as in the warmer parts of the Old World. One divi 

 sion of the family, containing numerous species abounds on the sandy 

 shores of the tropical seas. The others are all freshwater fishes. iSo 

 far as the vertebric in the ^iltiridw have been examined, no conclusions 

 can be drawn. The vertebrje in the marine species range from 35* to 

 50; in the North American forms from 37 to 45,t and in the South 

 Ameiican fresh-water species, where there is almost every imaginable 

 variation in form and structure, the numbers range from 28 to 50 or 

 more. 



The Cypyinida\1i. confined to the fresh waters of the corthern hemi- 

 si)here, and their analogues, the Characinidiv of the i ivers of South Amer- 

 ica and Africa, have also numerous vertebne, 3G to 50 in most cases. 

 I fail to detect in either group any relation in these numbers to sur- 

 rounding conditions. 



In general, we may say of the soft-rayed fishes that very few of them 

 arc iidiabitants of tropical shores. Of these few, some which are closely 

 related to northern forms have fewer vertebriie than their cold-water 

 analogues. In the northern species, the fresh-water species and the 

 species found in the deep sea, the number of vertebrte is always large, 

 but the same is true of some of the tropical species also. 



SPINY-RAYED FISHES. 



Among the spiny-rayed fishes, the facts are more striking. Of these, 

 numerous families are chiefly or wholly confined to the tropics, and in 

 the great majority of all the species the number of vertebne is con- 

 stantly 24,§ 10 in the body and 14 in the tail (10 + 14). 



In some families in which the process of ichthyization has gone on to 

 an extreme degree, as in certain Flectognath fishes,|| there has been a 



* Tachisurus, Felichthys, etc. 



t Ictalurus, Ameiiirns, etc. 



t Carp, minnows, snckers, cliubs, bnffalo fishes, gnilgeons, etc. 



^ This is true of all or nearly all the Serranidn , Sparidtr, Scuniida, Cho'todoiilidtf, 

 Hamulida', Gevridw, Gobiidtv, Jcantlturida', lliujilida-. .s^(//^/(t7(u/(C; MuUUiiv, /'(///lacc/i-. 

 trida; etc. 



\\ Bdlistes, the trigger fish, 17; ^f(^nacantl^us and Ahitera, foollishes, abont 20; the 



trunkfish, Os<jaciow, 14; the putters, TelraodoH and Spheroides, 18; Canthiija>iler, 17 ; 



and the head fish, Mola, 17. Among the I'ediculates, Malthe nni] Atiieiuiariiin have 17 



t* lU vertebrie, while in their near relatives, the anglers, Lophiidw, the number varies 



Proc. N. M. 91^ -8, 



