Classification of the Scombroid Fishes. 7 L 



similar to the soft dorsal ; each pelvic fin of a spine and 

 5 soft rays or reduced to a spine only ; caudal fin present. 

 Rays of the spinous dorsal equal in numb 'r to the vertebrae 

 below tlienij each interneural usually attached to a neural 

 spine ; rays of soft dorsal and anal more crowded (except 

 the isolated finlets, when present), about twice as numerous 

 as the corresponding vertebrae ; pelvic bones separate, 

 anteriorly extending forward to the cleithra and firmly 

 imbedded in the ligament between them. Vei'tebrse 

 31 (15 + 16) * to 53 (28 + 25); anterior prsecaudals without 

 parapophysps, with sessile ribs ; posterior prsecaudals with 

 ribs attached at the extremities of closed haemal arches ; 

 epipleurals attached to the centra. 



Epinnula, Ruvettus, Thyrsites, Nealotus, Prometichthys, 

 Gempylus. 



The Oligoceae Thyrsitocephalus appears to belong to this 

 family. 



Family 2. Trichiuridse. 



Body very elongate, strongly compressed ; maxillary 

 sheathed by the praeoibital ; spinous dorsal, if distinct, not 

 longer than the soft ; anal with numerous short spines ; 

 pelvic fins reduced to a pair of scale-like appendages, or 

 absent ; caudal small or absent. Dorsal and anal rays 

 corresponding to the veitebi'se, ea'h interneural or inter- 

 haemal attach, d to a neural or hyemal spine ; pelvic bones, 

 if present, united to form a slender spicular bone connected 

 with the cleithra by a loug ligament. Vertebrae numerous, 

 100 (43 + 57) to 159 (39 + 120) or more; ribs feeble, 

 sessile. 



Aphanopus, Evoxymepoton, Lepidopus, Benthodesmus^ Eu- 

 pleurogrammus , Trichiurus. 



Lepidopus is known from Oligoceae deposits. 



Division II. Scombriformes. 



Hypinal nearly or quite hidden by the deeply forked 

 base's of the caudal tin-rays. Fraeinaxillaries beak-like, free 

 from the nasals, which are separated by the ethmoid ; mouth 

 toothed, with lateral cl^f t ; no canines. Epiotics separati^d 

 by the supraoccipital. Gill-membranes free from the isthmus. 

 Pectoral tins placed high. 



* I am indebted to Dr. Gill for a radiograph of ^^/w/u/Za, which shows 

 the vertebrae to number 31 (15+16). In Thyrsites prometlieus there are 

 34 vertebrae. 



