412 Memoir Sears Foundation for Marine Research 



Description. Proportional dimensions in per cent of total length. Male, 886 mm., 

 from Rio de Janeiro (Harv. Mus. Comp. Zool., No. 463). 



Trunk at origin of pectoral: breadth 7.9; height 10.7. 



Snout length in front of: outer nostrils 3.3; mouth 7.1. 



Eye: horizontal diameter i.O. 



Mouth: breadth 6.3; height 3.5. 



Nostrils: distance between inner ends 18.1. 



Gill opening lengths: ist 3.2; 2nd 3.45 3rd 3.7; 4th 3.5; 5th 2.9. 



First dorsal fin: vertical height 14.7; length of base 9.8. 



Second dorsal fin: vertical height 4.1; length of base 4.1. 



Anal fin: vertical height 5.15 length of base 8.5. 



Caudal fin: upper margin 29.5; lower anterior margin i i.i. 



Pectoral fin: outer margin 13.9; inner margin $.6-j distal margin 14.0. 



Distance from snout to: ist dorsal 27.5; 2nd dorsal 59.5} upper caudal 70.55 



pectoral 21.3; pelvics42.5; anal 55.3. 



Interspace between: ist and 2nd dorsals 21.2; 2nd dorsal and caudal 7.6; anal and 



caudal 5.8. 



Distance from origin to origin of: pectoral and pelvics 20.3; pelvics and anal 14.6. 



Trunk about Vs as high at origin of ist dorsal as its length to origin of caudal j more 

 strongly compressed than in other local species. No mid-dorsal ridge. Caudal peduncle 

 about % as wide as deep, the upper precaudal pit strongly developed as a narrow, trans- 

 verse, lunate furrow, the lower pit similar but much smaller. Dermal denticles evenly 

 and closely spaced, overlapping but little, the blades thick and rather strongly arched, 

 broader than long, strongly sculptured, usually with 5 (occasionally only 3) high, sharp- 

 topped ridges separated by V-bottomed valleys, the marginal teeth broad and short, the 

 axial only very little the longest; pedicels long, rather slender, the four corners of bases 

 short. 



Head in front of pectoral a little less than Vs of length of trunk to origin of caudal, 

 its dorsal profile sloping steeply, very thin anterior to eyes, hammer-shaped, the outer 

 posterior margins nearly straight and transverse or even sloping slightly forward (much as 

 in tudes) ; the breadth of head at eyes about 1.2 times its length to origin of pectorals, and 

 about 3.3 times its length at oculo-narial prominence; anterior margin of hammer 

 scalloped with a deep, rounded indentation in midline (as in diplana\ a shallower 

 indentation opposite each nostril (much shallower than in diplana or zygaena) and a 

 still more shallow sinuosity between the two others; a well marked groove running inward 

 from corner of nostril along anterior margin of head about Vs of distance toward mid- 

 line (much more strongly marked than in tudes). Distance from anterior margin of eye 

 to anterior corner of oculo-narial prominence about equal to diameter of eye; a line con- 

 necting the inner ends of nostrils passes about midway between front of mouth and an- 

 terior margin of head, one through center of eyes passes anterior to mouth by a dis- 



