34^ Memoir Sears Foundation for Marine Research 



Figure 8i. Dasfatis americana, male, 505 mm %vide, from Molasses Key, Florida (Han-. Mus. Comp. ZooL, 

 No. 367). A Side view of midsector of tail to slightly larger scale. B Tip of tail spine, about 3.9 X - C Midsector 

 of tail spine, about 3.9 X. T> Cross section of tail spine about mid%vay of its length, about 3.9 X. 



Still is smooth-skinned to a size considerably greater than that at which £). americana 

 commences to show its characteristic mid-dorsal thorns. 



