Fishes of the Western North Atlantic 



471 



Figure 107. Rhinoptera bonasus, immature male, 567 mm wide, from Newport, Rhode Island (Harv. Mus. 

 Comp. Zool., No. 746). A Side view of head, about 0.6 X- B Lower surface of anterior part of head, about 

 0.6 X. C Side view of tail, about 0.6 X. 



Upper and lower dental plates strongly convex anteroposteriorly but only weakly 

 so transversely, the exposed margins usually irregular by loss of a tooth from one series 

 or another; front edges of teeth in front row often more or less damaged, the anterior 

 2—5 rows of teeth in each jaw worn flat by friction of lowers against uppers. Teeth 

 normally in seven series after birth (for embryonic serial arrangem.ent, see Develop- 

 mental Stages, p. 473); occasionally six or eight in one jaw or the other, ^^ in close-set 



30. Seven series both above and below in six United States specimens and in two from Brazil; seven above and eight 

 below in one from the United States and in one from Brazil; and six above and seven below in one from Brazil. 



