us 



PALEONTOLOGY 



to 



species, mostly of extinct genera. It is most 

 richly represented at the pre- 

 sent day by the Sphyrenoid, 

 Scomberoid, and Xiphioid 

 families. 



There are two kinds of ex- 

 isting sword-fish, Xiphias and 



Histiophorus ; in the former 



1 ' Fig. 61. 



the sword-like prolongation of Scales of a Scom- 

 the confluent premaxillaries is beroid fish, 

 flattened, in the latter it is rounded. 



Fossil remains of a rounded rapier-like 

 " sword," but much longer and more slender 

 than in the existing Histiophorus, have been 

 found in the eocene clay at Sheppy and 

 Bracklesham. They are referred to an ex- 

 tinct genus of the xiphioid family by Agassiz, 

 called Ccelorhynchus, or " hollowbeak." The 

 most perfect specimen hitherto found is 

 figured in fig. 62, of half the natural size. It 

 forms part of the instructive collection of 

 Captain Le Hon at Brussels. The upper 

 transverse section shows the single cavity at 

 the middle of the rostrum ; and the lower 

 section shows the double or divided cavity 

 near its base. 



Order V.— ANACANTHINI. 

 Char. — Endo-skeleton ossified ; exo-skeleton 

 in some as cycloid, in others as ctenoid 

 scales ; fins supported by flexible or 

 jointed rays ; ventrals beneath the 

 pectorals, or none ; swim-bladder with- 

 out air-duct. 



