21. MYLIOUATIS. 489 



each side. Tail very long and thin, with a dorsal fin near its root ; 

 generally a serrated spine behind the fin. 

 Temperate and tropical seas. 



The dentition of the species of this genus undergoes great changes 

 with age. There is no median series of larger teeth in very young 

 examples, but alj the teeth are of equal size and regularly hexan- 

 gular. The tail is much longer in young examples than in old 

 ones, and the coloration more ornamental. Singularly enough, the 

 serrated caudal spine is frequently absent. 



1. Myliobatis aquila. 



Aquila marina, liellmi. De Aquat. pp. 96, 97 ; Salvian. p. 146 ; Jon- 



ston. De Pise. pi. 9. tigf. 9 ; Willuyhby, p. 64, tab. C 2. 

 Pastiuacae, species 2'^«, Rondel, p. 338. 



Aquilone, Columna, Aquat. et Terrestr. atmn. observat. pp. i, ii. 

 Raja, sp. no. 5, Artedi, Gen. p. 72 ; Synon. p. 100. 

 Raja aquila, L. Si/st. Nat. i. p. 390 ; Briinn. Pise. Mass. p. 3 ; Blocli, 



taf. 81 ; Bl. Schn. p. 3G0; Risso, Ichth. Nice, p. 9. 

 Duhamel, Pesch. iii. sect. ix. p. 283, pi. 10. 

 Whip-Ray, Penn. Brii. Zool. iii. p. 88, and edit. 1862, iii. p. 128 ; 



Jenyns, Man. p. 519. 

 Myliobatis aquila, Ciiv. Rkyne An. ; Risso, Etir. Merid. iii. p. 162 ; 



Yarrell, Brit. Fish. 2ud edit. ii. p. 591, or, 3rd edit. ii. p. 595 ; 



Man. Sf Ilenle, p. 176 ; Couch, Fish. Brit. Isl. i. 135, pi. 32 ; Du- 



meril, Elas7nobr. p. 634. 

 Pastinaca aquila, Gronov. Syst. ed. Gray, p. 12. 



Body entirely smooth. The skinny prolongation of the snout is 

 obtuse, and but moderately produced. Median teeth of the upper jaw 

 from four to six times as broad as long. The insertion of the dorsal 

 fin is behind or opposite the extremity of the ventral fins. Orbit 

 with scarcely a trace of a projection above. Coloration uniform. 



Mediterranean, Atlantic, Australian seas. 



a. Adult female : stuffed. England. From Mr. Yarrell's Collection. 

 6. Half-grown female : stuffed. Berwick. From Mr. Yarrell's Col- 

 lection. 



c. Adult male. Madeira. Presented by J. Y. Johnson, Esq. 



d. Adult female : stuffed. 



e. Adult male : stuffed. 

 /. Half-grown. 



The following specimens have narrower teeth, those in the upper 

 jaw being only twice as wide as long. They arc very young ex- 

 amples, and thei'efore this may be only a difference due to age. 



g,h. Young. Sydney. 



i. Young : stuffed. Presented by G. Rose, Esq. 



3. ELinoptera vespertilio, Girard, Proc. Ac. Nat. Sc. Ph'dad. 1856, p. 137, 

 and Bost. Journ. Nat. Hist. 1857, p. 544, pi. 26, or U. S. Pac. PR. 

 E.rped. Fish. p. 375 ; Holorhinus vespertilio. Gill, Proc. Ac. Nat. Sc. 

 PkUad. 1862, p. 331 ; Myliobatis californiciis, Gill. Ann. Lye. Nit. 

 Hist. New York, viii. p. 137. — California. 



