NATURAL SCIENCES OF PHILADELPHIA. 125 



D. Dorsal spines not more than 22. 

 a. Vomer unarmed, 

 al. Dorsal and anal finlets 6. Corslet not 



scaly. First dorsal XIV , Gymnosarda. 



a2. Dorsal finlets 8 9. Anal 7 9. 



Corslet with very small scales. D. XI. 



XIII Orycnopsis. 



Corslet with larger scales. D. XVIII. 



XXII Sarda. 



aa. Vomer and palatines dentigerous. 



b. Teeth of jaws rather small. Corslet on 

 the sides before formed by larger 

 scales. D. XII. XV. 



Lateral line simple Orycnus. 



Lateral line double Grammatorycnus. 



bb. Teeth of jaws strong. Corslet obsolete 

 and body generally partly naked. 

 Teeth compressed, nearly equal in each 

 jaw. Dorsal and anal finlets similar, 



710. D. XIV. XVI. (XX.) Cybium. 



Teeth conic, much larger in the lower. 



Dorsal and anal finlets 4 5. D. XII...Lepidocybium. 

 Teeth conic, subequal. Dorsal and anal 



finlets 39. D. XV. XVIII Apodontis. 



DD. Dorsal spines 25, Acanthocybium. 



CC. Tail not keeled, 

 a. Ventrals I. 5. 

 al. Dorsal and anal finlets developed. 



1. Lateral line present. 



Dorsal and anal finlets 6. Lateral line 

 abruptly decurved behind the last 

 spines Thyrsites. 



Dorsal finlets 5 ; anal 4. Lateral line 



nearly straight Thyrsitops. 



2. Lateral line obsolete. Skin with spini- 



gerous or stellate tubercles Ruvettus., 



a2. Dorsal and anal fins undivided Epinnula. 



aa. Ventrals represented chiefly by the spines. 

 Preoperculum unarmed. Dorsal and anal fin- 

 lets 2 Prometheus. 



Preoperculum spinigerous at its angle. Dorsal 



and anal finlets none Dicrotus. 



AA. Body very long, (height much less than a tenth of the 



length.) First dorsal with numerous spines Gempylinje. 



Spinous dorsal XXX., XXXI. Ventrals minute, I. 5 Gempylus. 



The types of the respective genera are the following: 



SCOMBRINLE (Bon.) Sw. 



1. Scomber (Z.) Scomber scombrus L. 



2. Auxis (Cuv.) Scomber Rochei Risso. - 



ORYCNIN.E Gill. 



3. Orycnus (Cuv.) Scomber alatunga L. S. thynnus L. 



4. Grammatorycnus (Gill.) Thynnus bilineatus Riippell. 



5. Gymnosarda (Gill.) Thynnus unicolor Riippell. 



1862.] 



