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. 

 Thynnvs thynnus, L. (AfterGiinther.) 



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. 



Gastrodiisma inelamjms, Rich. The lower figure shows the groove into which the pelvic Hn.s 

 can be folded. (After Giinther.) 



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

 Lepidopus, 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- 



