Figure 1. — More than 95 percent of the specimens of scyliorhinids from the western North Atlantic available for 

 study have been collected within the 100- to 300-fathom (183- to 914-m.) depth range shown here. 



tively large number of unnamed species exist, tin- 

 described not because their differences from other 

 species have not been recognized, but undescribed 

 because examples have not yet been caught. For 

 this study, more than half the specimens have been 

 collected within the past five years. 



To anticipate in detail the needs of future 

 studies is presumptuous, but some of the char- 

 acters of the genera of the cat sharks of the west- 

 ern Atlantic that have been little used in orthodox 

 or classical studies seem worth discussion even 

 though these cannot be fully utilized in reaching 



taxonomic decisions in this geographically limited 



study. 



Color and color pattern 



Western Atlantic cat sharks fall in two groups 

 with respect to color pattern. All Apristurus are 

 nearly uniform in color, and preserved specimens 

 are either black or dark brown of various shades 

 but with no tendency to the formation of any 

 pattern. A few specimens that I have seen 

 brought to the surface from hauls in the northern 

 Gulf of Mexico were uniform black, but these 

 became either very dark gray or dark brown after 



REVIEW OF WESTERN ATLANTIC CAT SHARKS 



585 



