466 



TELEOSTEI 



Family TRICHIUBIDAE. The pectoral fins are inserted low clowu, 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 



FIG. 493. 

 Thynnus thynnv.s, 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 pelvics? are likewise lost. The teeth become very 

 powerful and sharp. 



Fio. 494. 



r it*. 41*-*. 



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

 can be folded. (After Giinther.) 



Tkyrsitocephalus, von K. ; Oligocene, Europe. TJiyrsites, C. and V. ; 

 L&pidopus, Gou. (Fig. 495) widely distributed ; Oligocene, Europe. 

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

 496) ; Benthodesmus, Goode ; Eupleurogrammus, Gill ; Gempylus, C. and V. 



Family CORYPHAENIDAE. The body is elongate, compressed, with 

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



