FISHERY BULLETIN': VOL. 69, NO. 3 



Table 1. — Oceanographic data for lago omanensis from Final Cruise Report, Anton Bruun Cruise 4B, Woods Hole 



Oceanographic Institution (1965). 



mens are deposited in the collections of the U.S. 

 National Museum, California Academy of Sci- 

 ences, and the British Museum (Natural His- 

 tory) . 



DESCRIPTION 



Proportional dimensions as percentages of 

 total length are given for our 16 specimens in 

 Table 2. 



In lateral view head outline slightly convex 

 dorsally and ventrally, its outline tapering 

 smoothly to snout tip; outline of head in dorsal 

 view parabolic in shape, the sides converging 

 at a narrow angle from gill openings to nostrils 

 but then converging at a much wider angle to 

 snout tip; head broad, width at spiracles about 

 half its length; interocular slightly less than 

 width of head at eyes; head subquadrate in 

 transverse section at eye pupils. 



Snout tip narrowly rounded in dorsal view, 

 bluntly pointed in lateral view; preoral length 

 1.1 to 1.4 in mouth width. 



Eye length equal to or slightly longer than 

 distance between nasal apertures; eye openings 

 subelliptical, rounded anteriorly. 



Nictitating lower eyelid (NLE) a variety of 

 Compagno's (1970) transitional type, interme- 

 diate in form between "nictitating folds" and 

 "nictitating membranes" of authors (Figure 

 2B); its anterior edge smoothly confluent with 



edge of upper eyelid ; secondary lower eyelid 

 ( SLE ) originating beneath origin of NLE ; post- 

 eriorly NLE merges with SLE and continues as 

 single edge to notch; subocular pouch or pocket 

 between NLE and SLE extends beneath anterior 

 two-thirds of eye; SLE edge sharp and thin with 

 NLE is artificially raised to the limits of its 

 travel; dermal denticles present on outer face 

 of NLE. The structure and the kinetics of the 

 NLE in [a(jo omanensis suggest that it cannot 

 cover the potserior third of the eye when raised 

 as it can in adults of Galeorhinus and higher 

 carcharhinoids. 



Spiracles open below level of posterior eye 

 notch and are posterior to eye by distance about 

 equal to their own length. 



Gill openings increasing in size from first to 

 third by small increments, with fourth slightly 

 shorter than third and fifth about half length of 

 fourth, becoming more dorsally situated from 

 anterior to posterior, with upper origin of first 

 opposite midpoint of fifth. Definite gill rakers 

 not developed, but small dermal mounds are 

 jn-esent on gill arches. 



Nostrils relatively large, their openings 

 obliquely directed anterolaterad; anterior nasal 

 flap varying from subtriangular to lobate; a 

 small inner nasal flap present dorsal to anterior 

 nasal flap and concealed by it; posterior nasal 

 margin with an elongated process (.stiffened by 

 ala nasalis) that projects obliquely dorsomedially 

 into nasal cavity. 



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