66 contributions to noeth american ichthyology iv. 



Dasibatis tubeeculata. 



Maja tuberculaia Lac^p. ii, p. 106, pi. 4, fig. 1. 



Raja tiihercalata Shaw, Gen. Zool. v, jit. 2, p. 290, pi. 127. 



Tnjgon gymnura Miill. Ermau's Reise um die Ercle, j). 25, Taf. 13. 



Trijffon osteostlcta Miill. 1. c. p. 25, Taf. 14. 



Trijfjon iuberculata Dunieril, Elasraobr. p. 605. 



Trygon tnhcrculatu Giinilier, Cat. viii, p. 480. 



Disk quadrangular, a little wider than long. Snout produced, sharp 

 pointed. Anterior aud posterior margins nearly straight, the anterior 

 curved near the outer angle to meet the posterior, and the latter curved 

 near the hinder angle to meet the inner. Tail nearly three times the 

 length of the disk, with a slight ridge above and a narrow cutaneous 

 exiiansion below, roughened with small spines similar to those on the 

 head, bearing a long serrated spine. A row of elongated tubercles on 

 the dorsum and anterior portion of tail and one or more smaller ones on 

 each shoulder. The j)osterior tubercles of the median row are so much 

 elongated as to resemble the spine. Mouth much undulated, with three 

 papilliB. Teeth small, unequal. Color yellowish to olivaceous brown, 

 darkening with age. The young are without scales or tubercles. As 

 the animal grows older and the tubercles appear a few scattered asperi- 

 ties appear on the head ; still later these increase in number and size to 

 such an extent as to cover the head and dorsum with a heavy coat of 

 mail made up of the closely-set flattened scales. The tubercles of the 

 back cease growing as the scales enlarge, and ultimately there is little 

 distinction between them. Usually the tubercle on the middle of the 

 pectoral arch is larger ; those on the tail continue to increase in size 

 with age. A young female measures in length of body 9.9, length of 

 tail 28.2, and width of disk 11.0 inches. 



Cannavierias, Surinam, Para, Bahia, and Rio Janeiro. 



Dasibatis longa. 



(Garman, 1880, Bull. Mns. Comp. Zool. vi, p. 170.) 



Disk quadrangular, about one-sixth wider than long. Margins nearly 

 straight, anterior meeting in a blunt angle on the end of the snout. 

 Outer angles rounded, posterior blunt. Ventrals rounded. Tail more 

 than twice as long as the body, roughened with small asperities, de- 

 pressed anteriorly, compressed behind the spine, keeled above the com- 

 pressed portion, with a long, narrow cutaneous expansion on the lower 

 side. Mouth curved with five papillre. A row of small tubercles behind 

 the head ou the shoulder girdle. It is likely that larger specimens are 

 provided with tubercles on back and tail. 



