372 Memoir Sears Foundation for Marine Research 



tip narrowly rounded in adults but more broadly rounded in young, the lower lobe 

 (expanded lower anterior corner) about % (40 to 44%) as long as upper and with sub- 

 acute tip, the re-entrant corner, included by the two lobes, well rounded. Distance from 

 origin of caudal to tip of anal nearly or quite as long as base of anal. Anal about as long at 

 base as 2nd dorsal, and about as large in area, but with subacute apex and much more 

 deeply concave posterior margin, its free rear corner about % as long as base. Distance 

 from origin of anal to tips of pelvics a little longer than base of anal. Pelvics a little longer 

 at base than anal. Pectoral nearly as long (87 to 97%) as head to origin of pectoral in large 

 specimens but relatively somewhat shorter (about 73%) in small, a little less than twice 

 as long as broad, the outer margin only weakly convex, distal margin only weakly concave, 

 the corners very narrowly rounded in adult but somewhat more broadly so in young. 



Color. Varying from slate-gray to brownish gray or brown above, perhaps depending 

 on color of the environment; a pale tint of the same hue, or whitish, below; fins without 

 any conspicuous markings. When the shark is newly caught some of the dermal denticles 

 may be brilliant blue, at least in Florida specimens. 



Size. The usual size at birth is said to be about 22 inches (weight about 2V2 pounds). 

 Maturity is attained at about six feet and it appears that very few reach as great a length 

 as eight feet; 7 feet lO inches is the longest of which we find unquestionable record.*" If 

 one about three feet long, taken near New York on June 9, was born the previous sum- 

 mer or early autumn, as seems probable,*" milberti may be expected to grow by about lO 

 inches during the first winter, for the newborn young of 25 to 26 inches have been taken 

 in that general region in September. But nothing whatever is known of the subsequent 

 rate of growth. 



Usual weights of adults are about 100 pounds at six feet, 125 to 130 pounds at about 

 seven feet, 200 pounds at about 7 feet 8 inches. 



Develofmental Stages. Presumably milberti is viviparous, but whether the young 

 develop placental connection with the mother has not yet been definitely established. Em- 

 bryos resemble the adults in general; 6 to 13 are recorded in a litter, the usual number 

 being 8 to 1 2, with the two sexes about equally represented. 



Habits. Although this is undoubtedly the most abundant member of its genus in 

 season along the middle Atlantic coast of the United States, and the one most often seen, 

 knowledge of its habits is scant. Certainly it is littoral rather than pelagic, for considerable 

 numbers enter shallow bays, harbors and river mouths; hence, they are often harpooned or 

 taken in pound nets, and it is said to be the only large shark that regularly visits the small 

 bays on the north shore of Long Island, New York, as it and others also do the much more 



85. Two specimens of milberti of 8 feet 6 inches have been reported from New Jersey, but by name only (Fowler, 

 Proc. Acad. Nat. Sci. Philad., 72, 1921 : 386) ; an old report (Baird, Rep. Smithson. Instn. [1854], 1855: 352) 

 that the largest in New Jersey waters are of about nine feet may not have been based on actual measurements; 

 and the report of a North Carolina milberti of 9 feet 2 inches (Smith, Bull. N. C. geol. econ. Surv., 2, 1907: 

 35) actually may have referred to some other shark, so far as the brief account goes; perhaps ta the larger- 

 growing obscurus. 



86. Nichols and Breder, Zoologica, N. Y., 9, 1917: 16. 



