CG coNTKii.rnoNS TO NORTH AMERICAN ICHTHYOLOGY iv. 



DVSIHATIS TUBERCULATA. 



/.. ' I .l"i-p. ii. ]). Idll. pi. .J, f| U r. 1. 



:!,itn >ii:i\v. Ceil. /diil. V. pi. '.'. ]i. M'.HI, ]il. I'JT. 



'irijijtui itfni'iinrii Miill. Knnim's K'IMM- nni <lic Krdc, p. 'Jo, Taf. 13. 

 Ed Miill. 1. c. p. ^->. T.-ir. 1 I. 

 Ufa I iiiiiH-ril, KhisMinlir. p. <iH.">. 

 </< tiilni-1-nlntti (iiinllnT, <_';it. viii, p. 



quadrangular. a lit lie wider than long 1 . Suout produced, sharp 

 pointed. Anterior and posterior margins nearly straight, the anterior 

 enrved near t!:e oilier 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 

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

 head, 1 >ea; in- a long serrated spine. A row of elongated tubercles on 

 i he dorsnm and anterior portion of tail and one or more smaller ones on 

 each shoulder. The posterior tubercles of the median ro\v are so much 

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

 papilla-. Teeth small, unequal. Color yellowish to olivaceous brown, 

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

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

 ties appear on the head ; still later these increase in number and si/.e to 

 Mich an extent as to cover the head and dorsnm with a heavy coat of 

 mail made up of the closely-set llatteiied 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 L'S.-J, and width of disk 11.0 inches. 



Canna\ ieiias, Surinam, Para, Uahia, and K'io Janeiro. 



DASIMATIS LO.NCA. 



IM.-III, 1--H, Hull. MM-;. rump. /,;;]. vi, p. ITU.) 



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

 Mrai-lii, anterior meeting in a blunt angle on the end of ihe snout. 

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

 than l\\ice as l.uig as the body, roughened with small asperities, de- 

 p: - -d anteriorly, compressed behind the spine, keeled above the com- 

 proscd portion, with a long, narrow cutaneous expansion on the. lower 

 side. Mouth curved v, ith live papilla-. A row of small tubercles behind 

 the head on the shoulder grdle. It is likely that larger specimens are 



viilcil with tubercles on back and tail. 



