472 Memoir Sears Foundation for Marine Research 



quincunx mosaic; edges of successive teeth in contact but not overlapping; those of 

 median five series hexagonal, those of outermost series on either side pentagonal, those 

 of any supernumerary series tetragonal. Teeth of median series about twice as wide 

 transversely as those of next series outward and "^^—c^ times as wide as those of outermost 

 series; transverse breadths of teeth of all series about the same in oldest rows as in 

 youngest; some specimens with teeth of all series about as long anteroposteriorly in 

 oldest rows as in youngest, but others with teeth in youngest (most posterior) rows about 

 twice as long as in oldest, with regular gradation from oldest to youngest ; 1 1 to 1 2 rows 

 exposed and in function simultaneously in upper jaw, 12—13 i" lower jaw of large spec- 

 imens, 7 or 8 in each jaw of smaller ones. 



Subrostral fin forming two rounded lobes, one continuous with the other at bottom 

 of deep dividing notch, extending only a little beyond front of forehead from which it is 

 marked off by a deep transverse groove, and traceable rearward about to level of mouth 

 but at a lower level than main portions of pectorals. Dorsal fin with nearly straight 

 anterior margin, its posterior margin abruptly concave basally and prolonged rearward 

 for a short distance in acute triangular form, free from tail; its apex narrowly rounded; 

 its origin about opposite axils of pectorals; its base a little less than half as long as 

 distance between spiracles. Pelvics with anterior and inner margins nearly straight, 

 distal margin evenly and rather strongly convex; corners abruptly rounded; anterior 

 margin nearly as long as distance from origin of pelvic to inner rear corner. 



Color. Brownish above, lighter or darker, sometimes of a yellowish tint. Lower 

 surface white or yellowish white, with outer corners of pectorals more or less brownish; 

 some specimens marked both above and below with many narrow obscure dark lines 

 or bands radiating outward from center of disc." 



Size. It seems that the breadth at birth is about 14 inches, for an embryo 1372 

 inches wide has been recorded, ^^ while our Study Material includes a Brazilian specimen 

 only a little larger (365 mm or about 14 Va in- wide) but probably free living, since it 

 has lost its primary embryonic teeth and all traces of its umbilical scar. 



It appears that there is a considerable variation in the size at which sexual maturity 

 is reached, either between individuals of the same geographical locality or those in dif- 

 ferent parts of its range. Thus, the testes of a male only 26—28 inches wide from North 

 Carolinia waters were greatly enlarged '^ and a female of 24 inches contained embryos,^* 

 whereas the claspers of a Brazilian male 780 mm wide (about 31 in.) in our Study 

 Material still reach only about halfway along the inner margins of the pelvic fins. 

 Evidence as to the maximum size to which the species ordinarily grows is similarly 

 contradictory. Its describer^* wrote of it as a "large species," with full-grown specimens 

 weighing about 100 pounds; more recently a well known ichthyologist has stated that 

 some of those observed in Florida were seven feet wide.^* However, the only sexually 



31. A Cuban specimen is so pictured and described by Howell-Rivero (Mem. Soc. cubana Hist, nat., i$, 1941: 261, 

 pis. 26, 27). 



32. Gudger, Amer. Nat., 44, 1910: 397. 33. Gudger, Proc. biol. Soc. Wash., 26, 1913: 102. 



34. Gudger, Amer. Nat., 44, 1910: 397. 35. Mitchill, Trans. Lit. philos. Soc. N. Y., i, 1815: 479, 480. 



36. Smith, N. C. geol. econ. Surv., 2, 1907: 47. 



