Fishes of the Western Northi Atlantic 



373 



extending rearward beyond extremity of upper tailfold for a distance about equal to 

 distance between orbits, its maximum width usually a little greater than depth of tail 

 midway of the fold; origins and terminations of tailfolds indefinite. Length of tail from 

 center of cloaca 1.7—2.6 times as great as distance from center of cloaca to tip of snout 

 in specimens with tails apparently intact; distance from center of cloaca to tail spine 

 about half as long as that from cloaca to snout. 



Tail spine (or spines) more slender than in other western Atlantic species; length 

 of free portion (if fully developed) a little less to a little greater than distance between 



Figure 89. Dasyatis sabina. A Upper right-hand tooth band of female, 

 268 mm wide, from Florida (Harv. Mus. Comp. ZooL, No. 84), and B 

 Upper left-hand tooth band of male, 271 mm wide, from Amelia Island, 

 Florida (Harv. Mus. Comp. ZooL, No. 121), the symphysis marked in 

 each case by a broken Une, about 4X. C Tip, D Middle part, and E 

 Cross section of middle part of tail spine of male shown in Fig. 88, 

 about g.6x. 



outer margins of orbits; total length of spine from origin 1.25— 1.5 times that great; 

 maximum breadth of spine about 4.5 "/o as great as its total length; lateral teeth 32—38 

 on specimens counted, their outer cutting edges as illustrated in Fig. 89D. Commonly 

 one tail spine, but often two, the replacement spine (in specimens seen) close behind 

 the older one."" 



Skin, apart from tail spine, perhaps wholly naked on newborn specimens, but a 

 large median tubercle soon develops over pectoral girdle; midline of disc of specimens 

 one-third grown with about 6—8 large tubercles with narrow median crest, sloping 

 anteriorly but vertically truncate posteriorly; larger individuals of both sexes have up 

 to 12—15 tubercles irregularly spaced on disc, 6—8 along anterior part of tail to spine, 



no. We have seen six specimens (all about 165 mm broad) from Texas with two spines, in all of which the order of 

 succession was as above. For further discussion, see p. 336. 



