THYSAN0UR2E OF THE UNITED STATES. 11 



dages pendant from the extremity of the. lower jaw; 

 pectoral fins broad and long, exceeding a little the 

 base of the dorsal ; ventral fins very long, originating 

 near the middle of the body ; dorsal and anal fins 

 large and truncated ; the pectoral and ventral mark- 

 ed with brown bands. 



Observations. — This species, as well as E. fas- 

 ciatus, presents brown bands upon the pectoral and 

 ventral fins ; the head is also equally flattened above, 

 and carinated under the gorge. The under side of 

 the body is, however, shorter, less elongated, with 

 the third ray of the ventral fin longer : the anal fin 

 smaller than the dorsal. The caudal fin lunulated, 

 with the lower lobe longer. Scales over all the 

 body, along the lateral line, and on each side of the 

 abdomen. Eyes large, situated at the summit of the 

 head, and near the extremity of the mouth. Mouth 

 transverse, and rather large. 



Color, blue upon the back, argentine and blueish 

 along the sides. 



Hab. In the Gulf of Mexico. Communicated to 

 me by Mr. Nuttall. 



P.— V. 10.— D. 15. simple.— A. 8.— -C. 17. 



Descriptions of the Tliysanource of the United States* 

 By Thomas SAY.—ReadJYov. 2lst, 1820. 

 Genus Machilis, Latr. 

 Eyes compound, occupying almost all the head j 



