Fishes of tJie JVestern North Atlantic 163 



First dorsal fin: vertical height 2.3, 2.4; length of base 5.2, 4.9. 



Second dorsal fin: vertical height 2.1, 2.1; length of base 5.8, 4.6. 



Pelvics: anterior margin ii.o, 12.2. 



Distance: from tip of snout to center of cloaca 41.5, 42.2 ; from center of cloaca 



to 1st dorsal 44.6, 45.0; to tip of tail 58.5, 57.8; from rear end of 2nd 



dorsal base to tip of caudal 3.3, 3.4. 

 Interspace between: ist and 2nd dorsals 0.0, 0.0. 



Disc about i.i times as broad as long; maximum anterior angle in front of spir- 

 acles about 90° on smaller specimens but about 105° on larger; tip of snout rounded, 

 not noticeably projecting; anterior margins nearly straight or slightly sinuous, the outer 

 and posterior corners broadly rounded, the posterior margin weakly convex. Axis of 

 greatest breadth about 77— 78''/o of distance rearward from tip of snout toward axils 

 of pectorals. Tail with narrow lateral folds along its posterior two-fifths, widest oppo- 

 site pelvics; its length from center of cloaca about i.i — 1.2 times as great to first dorsal 

 and 1. 4-1. 5 times as great to tip of tail as distance from center of cloaca to tip of snout. 



Dorsal surface of disc on larger specimens with 2,-6 medium to large thorns 

 on radiate bases close behind tip of snout; several smaller ones along rostral cartilage; 

 a row of 5—6 large thorns around inner margin of orbit, preceded by a few smaller 

 ones close in front of eye; 1—2 larger thorns inward from inner end of spiracle; a 

 group of up to 12 — 14 o" nuchal region, small to large and irregularly distributed; 

 three large thorns on each shoulder region, arranged like the mathematical symbol for 

 the word therefore (.•.), with a few smaller ones between these and the median line; 

 also a median row of 30—35 from nuchal region to first dorsal (six from pectoral 

 girdle to level of axils of pectorals), widely spaced anterior to level of axils of pectorals 

 but closer together and decreasing a little in size toward first dorsal; tail with one to 

 two irregular rows along either side in addition to the median row, the row lowest 

 down on either side continuing about halfway along base of second dorsal. In addition 

 to the larger thorns, the entire upper surface of the disc, including the skin above the 

 eyes, is strewn with numerous smaller prickles on small specimens, except for naked 

 areas along the posterior margins, and on the tip of the snout which continue so up 

 to a length of 350 mm or more. With continued growth these marginal naked bands 

 widen and additional naked areas develop on either side posterior to the scapular region 

 as well as on either side of the rostral ridge, while the skin above the eyes loses most 

 of its prickles; also, the prickles are relatively smaller and more closely spaced than on 

 smaller specimens (illustrated by female 463 mm long, Fig. 30). Each side of the tail 

 below the outermost row of thorns has a narrow band of close-set prickles along the 

 anterior half, but thence rearward it is only sparsely prickly. And the prickles in this 

 band are relatively larger and more thorn-like on younger Skates than on older ones. 

 The dorsals of the smallest specimens are smooth, their upper parts are prickly on 

 somewhat larger ones (316 and 350 mm); but on the largest ones seen there are only 

 a few prickles. Caudal membrane smooth. The pelvics of some small specimens are 

 prickly on the central part of the posterior lobe, but they are smooth on most, whether 



