466 



TELEOSTEI 



Family Trichiuridae. The pectoral fins are inserted low down, and 

 the body much compressed. Starting from Mackerel-like forms, such as 

 Thyrsites, the body gradually acquires a very elongate, band-like shape. 

 At the same time the vertebrae increase in number, and the originally 



Fio. 493. 

 Thyrmus thynnus, L. (After Giinther.) 



distinct spinous portion becomes continuous with the soft portion of the 

 dorsal, the tail tapers to a point, while the caudal fin finally disappears, as 

 in Trichiurus. The pelvic* are likewise lost. The teeth become very 

 powerful and sharp. 





Pig. 494. 



Gastrochisma melampus, Rich. The lower figure shows the groove into which the pelvic im- 

 am be folded. (After Giinther.) 



Thyrsitocephalus, von K. ; Oligocene, Europe. Thyrsites, C. and V. ; 

 Lepidopus, Gou. (Fig. 495) — widely distributed ; Oligocene, Europe. 

 Epinnula, Poey ; Nealotus, Johns. ; Dicrotus, Gthr. ; Trichiurus, L. (Fig. 

 496) ; Bentkodesmus, Goode ; Eupleurogrammus, Gill ; Gempylus, C. and Y. 



Family ( 'okyphaknidae. The body is elongate, compressed, with 

 very blunt snout, and large deep head, on to which extends the tin- 



