FISHERY BULLETIN: VOL. 69, NO. 3 



Figure 6. — lago omanensis. Dermal denticles from side 

 of trunk below first dorsal fin, 582-mm female, scanning 

 electron microscope photomicrograph, scale line at lower 

 left equals 100 ^. 



(less than 0.1 mm long) present on anterior part 

 of palate and inner surfaces of branchial arches, 

 also irregularly and rather sparsely scattered 

 on tongue. 



Pectoral fins broad, subangular, with their 

 anterior margins convex, apexes rounded, post- 

 erior margins slightly convex, free rear tips 

 rounded, and inner margins convex, relatively 

 short, their anterior margins about an eye di- 

 ameter shorter than distance from snout tips 

 to first gill opening; pectoral inner margins long, 

 about 11/2 to 11/;! times pectoral base length; 

 posterior margin about ll/ij to iy-> times in 

 anterior margin; free rear tip of pectoral vary- 

 ing in position from below posterior end of first 

 dorsal base to last third of first dorsal base. 



Pectoral fin skeleton, as studied on radio- 

 graphs, somewhat similar to that of Galeorhiniis; 

 propterygium with 1 radial, mesopterygium with 

 3 or 4, segmented metapterygial axis with 10 to 

 12; metapterygial axis elongate, much larger 

 than anterior basals, with a distal set of seg- 

 ments; radials mostly divided into three seg- 

 ments (proximal, intermediate, and distal), 

 intermediates shorter than jiroximals or distals, 

 which are equal in length. 



Pelvic fins somewhat larger than anal but 

 smaller than second dorsal in area; pelvics in 

 some males relatively smaller than those of fe- 

 males; pelvics triangular, with anterior margins 

 slightly convex to nearly straight, apexes broadly 

 rounded to subangular, posterior margins nearly 

 straight, free rear tips acute (slightly attenuate 

 in some specimens) , inner margins straight; 

 pelvic anterior margins 2.6 to 2.8, posterior 

 margins 1.7 to 1.9, and inner margins 1.4 to 1.6 

 in comparable margins of pectorals. 



Claspers and associated secondary sexual 

 structures of males generally similar in basic 

 plan to those described for Galeorhimis galeus 

 (as "Galeiis mdgar-is") by Leigh-Sharpe (1921), 

 but differing in several details; claspers long, 

 more slender and more angular distally than 

 those of Galeorhmus with bluntly pointed, flat- 

 tened tips (Figure 5A) ; claspers of adult males 

 extending well beyond free rear tips of pelvics; 

 clasper groove roofed over and closed by its 

 overlapping sides from apopyle to hypopyle; 

 small pseudosiphon present mediodorsally, its 

 pouch extending anteriorly on clasper. Unlike 

 Galeorhimis, the pseudosiphon aperture is much 

 less prominent and is located relatively farther 

 from the clasper tip. Cover rhipidion very large 

 (scarcely developed in Galeorhinus) , formed as 

 a rounded flap completely covering rhipidion; 

 rhipidion evenly rounded (wedge-shaped in 

 Galeorhinus); pseudojjera present, dorsolateral 

 and opposite to the rhipidion edge (as in Galer- 

 hinus) ; unlike Galeorhinus, the pseudopera is 

 partially covered by another flap, here termed 

 the exorhi])idion, which originates laterad to the 

 pseudopera and extends posteriorly to cover part 

 of the rhipidion. Hypopyle opening at level of 

 pseudopera, cover rhipidion, and anterior third 

 of rhipidion. 



Clasper skeleton studied from radiographs of 

 six males. Terminology is modified from Junger- 

 son (1899) and White (1936, 1937). One basal 

 cartilage connecting clasper cartilage to pelvic 

 basipterygium; a small beta cartilage present 

 at the junction of basal cartilage and clasper 

 cartilage; details of terminal cartilages not 

 clear, but at least two terminals, a dorsal and 

 a ventral, are in'esent; clasijer cartilages heavily 

 calcified in adult males. 



622 



