496 Memoir Seats Foundation for Marine Research 



Description. Proportional dimensions in per cent of total length. Male, 328 mm., 

 fromLat. 39° 51' N., Long. 70° 17' W. (U.S. Nat. Mus., No. 1 18396). Female, 1,080 

 mm., from Banquereau Bank (Harv. Mus. Comp. ZooL, No. 35237). 



Trunkal origin of pectoral: breadth 12.2, 12.6; height 10.7, 11.2. 



Snout length in front of: outer nostrils 2.4, 1.95 mouth 8.8, 6.2. 



Eye: horizontal diameter 4.9, 3.4. 



Mo«//^.- breadth 7.6, 8.1 j height i.i, i.i. 



Nostrils: distance between inner ends 4.3, 3.1. 



Labial furrow length from angle of mouth: upper 3.7, 2.4; lower 2.6, 1.4. 



Gill opening lengths : ist 1.2, 1.8; 2nd 1.2, 1.7; 3rd i.r, 1.5; 4th 1.2, 1.2; 5th 



1.7, 1.6. 



First dorsal fin: vertical height 3.4, 3.7; length of base 5.2, 4.6. 



Second dorsal fin: vertical height 3.8, 4.4; length of base 5.8, 5.7. 



Caudal fin: upper margin 25.3, 20.4; lower anterior margin 15.4, 12.8. 



Pectoral fin: extreme length 13.4, 13.2; extreme breadth 7.9, 6.3. 



Distance from snout to: ist dorsal 34.7, 36.8; 2nd dorsal 61.3, 67.7; upper caudal 



74.7, 79.6; pectoral 23.8, 18.8; pelvics 57.3, 60.7. 



Interspace between: ist and 2nd dorsals 22.0, 24.2 ; 2nd dorsal and caudal 7.0, 8.0. 



Distance from origin to origin of: pectoral and pelvics 35.7, 43-5; pelvics and 



caudal 15.8, 17.5. 



Trunk subcylindrical, moderately stout, its height at ist dorsal between ^q and Vs ( 17 

 to 18%) its length to origin of caudal, without mid-dorsal ridge. Caudal peduncle with- 

 out lateral ridges or precaudal pits. Dermal denticles very large, except on fins and lower 

 side of head anterior to gills, and so closely overlapping as to form a continuous armor,' 

 the peduncles short and stout, the blades smooth, ovoid, flat or concave, with rounded 

 margins posterior to level of gills, but weakly sculptured with 3 or 5 ridges further forward 

 on head. 



Head about ^4 of trunk to origin of caudal, its dorsal profile weakly and evenly 

 convex, somewhat flattened anteriorly. Snout thick-tipped, very broadly ovate, notice- 

 ably short, its length in front of nostrils about ^/i to Vs as great as length In front of mouth, 

 its length in front of mouth a little less than % of length of head. Distance between nos- 

 trils about V2 as great as length in front of mouth. Eye oval, its outline about as 

 convex above as below, much smaller than in Centroscyllium, its horizontal diameter 

 about y2 as long as snout in front of mouth, its center about opposite front of mouth. 

 Spiracle about ^3 to V4 as long as diameter of eye, about level with upper margin of 

 latter. Gill openings much smaller than in Centroscyllium , about V2 as long as diameter of 

 eye, all of about equal length and evenly spaced, the 5th close in front of pectoral. Nostril 



3. The edges of the denticles are so sharp that one must handle Cenlroscymnus carefully, lest one's hands be cut. 

 The closely overlapping denticles are one of the most distinctive features of the genus. 



