534 



BULLETIN 100, UNITED STATES NATIONAL MUSEUM. 



iceps and longipes, are marked by two types of striae: the typical 

 striation is fine and irregular, and in addition to this there occur 

 coarser black cross lines. The black ring about the anus, surround- 

 ing also the posterior lens-shaped organ, is continued forward to and 

 about the smaller anterior organ. 



The cheeks and the surface of the preopercular region are bril- 

 liantly silvery; the opercle is dark, but with metallic luster: the 

 ventral half of the suborbital region and the space between the eyes 

 show a blackish color through the delicate superficial membranes. 

 The snout, between and before the nostrils, is translucent; the 

 mandible is mostly dark, but whitish along the lower lip; the end 

 of the maxillary is also whitish. The extreme whitish margin of the 

 buccal cavity lies just behind a dark area; the roof of this cavity is 

 silvery, but the tongue is whitish, as is also the region before it, 

 with the exception of a median black triangle, pointed forward ; the 

 branchial cavity is dark brown on its roof, and whitish on its lower 

 sides, but margined by a blackish band with an extreme whitish 

 edge on the opercular and branchiostegal membranes. The parietal 

 peritoneum is purplish brown, underlain with silvery. 



The vertical fins are usually clear, with a spot at the base of each 

 ray, but the first anal ray and the dorsal spines are sometimes 

 blackish; the distal half of the first dorsal fin is sometimes dusky, 

 as in the type of torvus. 



The specimens from the Tawi Tawi Archipelago, which are re- 

 garded as intergrades between aeger and torvus, agree with the pre- 

 ceding description in all characters but those showing intergrada- 

 tion toward torvus, as has already been discussed. 



Table of measurements in hundredths of length to anus (typical specimens 



of H. s. aeger). 



Albatross station 



Total length in mm 



Length to anus in mm 



Length of head. 



Length of orbit 



Width of interorbital 



Orbit to preopercle 



Width of suborbital 



Length of snout 



Length of upper jaw 



Length of barbel 



Depth of body 



Width of body 



Height of second dorsal spine 



Height of first dorsal base 



Interdorsal space 



Height of first anal ray 



Length of first pectoral ray 



length of second pectoraf ray 



Length of third pectoral ray 



Length of outer ventral ray 



Length of second ventral ray 



Soft rays , first dorsal 



Ventral rays 



Pectoral rays 



Gill-rakers, lower limb, second arch. 



5621 

 165 

 39 

 64 

 22 

 21 

 30 

 9 

 18 

 32 

 11 

 49 

 30 



5621 

 145 



36 



62 



23.5 



22 



30 

 ' 9 



19 



34 

 9 



45 



22 



42 



22 



61 



5621 



5621 



23.5 



53 



20 



13.5 



58 



48 



(aeger, feeble.) 



