370 Memoir Sears Foundation for Marine Research 



measurements by Stewart Springer of an 8o-inch specimen taken at Woods Hole in Aug. 

 1942, and of 3 females, 2,125 to 2,220 mm., from Englewood, Florida; also a full-term 

 embryo, 540 mm., taken in upper Chesapeake Bay (U.S. Nat. Mus., No. 83597). 



Distinctive Characters. Among the ridge-backed subdivision of the genus, milberti 

 after birth is made easily recognizable by the large size of the first dorsal and by its posi- 

 tion far forward (originating over the axil of the pectoral), and by the free rear corner 

 of the second dorsal which is only about as long as the base. The wide spacing of the dermal 

 denticles and their free edges without definite teeth are diagnostic also. 



Descriftion. Proportional dimensions in per cent of total length. Male, 747 mm., 

 from Virginia Beach (U.S. Nat. Mus., No. 104969). Male, 1,496 mm., from Buzzards 

 Bay, Mass. (Harv. Mus. Comp. Zool., No. 35370). 



Trunk at origin of fectoral: breadth 12.O, — ; height 12.9, — . 



Snout length in front of: outer nostrils 4.1, 3.3; mouth 8.2, 7.0. 



Eye: horizontal diameter 2.1, 1.5. 



Mouth: breadth 9.5, 8.5; height 4.7, 4.1. 



Nostrils: distance between inner ends 5.9, 5.5. 



Labial furrow length: upper — , 0.5. 



Gill opening lengths: ist 3.0, 2.7; 2nd — , 3.0; 3rd — , 3.2; 4th — , 3.0; 5th 2.5, 



2.4. 



First dorsal fin: vertical height 10.9, 12.4; length of base 13.3, 1 1.3. 



Second dorsal fin: vertical height 3.1, 2.9; length of base 6.0, 4.1. 



Anal fin: vertical height 3.5, 3.9; length of base 5.7, 5.0. 



Caudal fin: upper margin 26.7, 27.8; lower anterior margin 12.O, 12.1. 



Pectoral fin: outer margin 18.1, 20.4; inner margin 6.3, 6.$; distal margin 14.4, 



17.7. 



Distance from snout to: ist dorsal 28.3, 28. 7j 2nd dorsal 60.3, 61.3; upper 



caudal 73.3, 72.25 pectoral 24.7, 20.7; pelvics 49.1, 47.1; anal 61.5, 61.0. 



Interspace between: ist and 2nd dorsals 20.7, 22.5; 2nd dorsal and caudal 7.4, 



7.1 ; anal and caudal 7.4, 7.4. 



Distance from origin to origin of: pectorals and pelvics 27.4, 27. i ; pelvics and anal 



13-3, I4-4- 



Trunk comparatively stout, its height at ist dorsal a little more than Vs as great as 

 length to origin of caudal, with dorsal profile rather strongly arched. Midline of back 

 with a low but unmistakable dermal ridge from about under rear tip of ist dorsal to a 

 point about as far in front of origin of 2nd dorsal as length of base of latter; this also 

 discernible in embryos, though less prominent. Caudal peduncle % to % as thick as deep. 

 Upper precaudal pit strongly marked, obtuse-ovate in outline, the lower pit much smaller 

 than upper and hardly visible in small specimens. Dermal denticles widely spaced, seldom 

 if ever overlapping, the skin exposed between them, blades thick, strongly convex antero- 

 posteriorly, usually with 5 high, moderately sharp ridges separated by round-bottomed 



