152 FISHES OF MASSACHUSETTS. 



posed of much larger, wider, more prominent tubercles, 

 commences just beneath the posterior angle of the operculum, 

 and terminates on the same plane with the extremity of the 

 first row ; the tubercles having diminished in size as they ap- 

 proached the tail, as in the first row ; a third row, composed of 

 a small number of still larger tubercles, commences on a line 

 with the posterior portion of the ventral disk, and terminates 

 just in front of the anal fin, forming the outer boundary of the 

 abdomen. The two upper rows of tubercles are of the color 

 of the back ; the lower, colored like the abdomen ; the tuber- 

 cles of all these rows are granulated upon their sides, and have 

 a naked spine at their summit. Head covered with tubercles 

 similar to those of the body ; those on the lower portion of the 

 operculum larger than those on the other parts of the head ; 

 diameter of the eye one inch ; irides red ; distance between 

 the eyes, two and a half inches. Nostrils, tubular. Teeth 

 in the jaws sharp, and compactly placed ; a greater number of 

 rows of teeth in the upper, than in the lower jaw. Lips yel- 

 low. Just back of the top of the head, a compressed ridge 

 rises abruptly, and as abruptly stops, after passing a short 

 distance back ; its depth being in its middle equal to one third 

 of its length ; and its length equal to one third the body of the 

 fish ; this ridge is formed of distinct rays, which are very visi- 

 ble in the dried specimen ; the top of this ridge is covered 

 with tubercles precisely similar to those which compose the 

 middle row on the body ; directly back of this dorsal ridge is a 

 small flat surface composing the space between it and the dor- 

 sal fin, whose sides are armed with strong tubercles projecting 

 laterally. Immediately behind this space, commences the dor- 

 sal fin. 



The Dorsal fin is rather longer than high. 



The longest rays of the Pectorals equal to the width of the 

 base of these fins. 



The Yentrals, together with the anterior portion of the pec- 

 torals, form an oblong disk, of a bright yellow color, with six 

 well marked lines on each side of its centre, by which it is 

 enabled to attach itself very powerfidly to foreign substances. 



