HISTORY OF THE FISHES OF MASSACHUSETTS. 17 



which renders it movahle ; its margin is bordered by a wide membrane. The pre- 

 operculum is rather small and is triangular, slightly movable, and divided at its lower 

 portion by a horizontal, serrated, bony ridge, which terminates posteriorly in a naked 

 spine ; beneath this ridge, the inferior portion is corrugated and granulated ; from the 

 base of the preopercle, radii diverge to its upper portion. Suborbitar bones roughened 

 like the top of the head ; cheek-bones covered with elevated striae, slightly serrated 

 upon their whole lower margin, and strongly serrated anteriorly on each side of the 

 snout. A strong ridge upon the humeral bone, serrated on its under edge, terminating 

 in a naked spine. All the spines upon the head are much more acute in young 

 specimens. In front of the emargination of the frontal bony plate is a naked mem- 

 branous portion, equal in width to the distance between the eyes ; in this space, half 

 way between the eyes and the extremity of the snout, are situated the nostrils, the 

 posterior of which is the larger. Eyes oblong ; longest diameter equal to the distance 

 between the eyes. Jaws armed with numerous, small, card-like teeth ; upper jaw 

 projecting beyond the lower. Tongue colorless, fleshy. The lateral line arises above 

 the posterior angle of the operculum, and, curving slightly downwards to a line op- 

 posite the space between the dorsal fins, thence pursues a straight course to the tail. 



The first dorsal fin is situated in a groove which partially receives it when closed, 

 and arises just back of a line with the termination of the occipital spines ; it is longer 

 than high. Its first ray is spinous, and serrated upon its entire anterior edge ; the 

 second and third rays are serrated at their upper anterior portion ; the third and fourth 

 rays are the longest. It is composed of ten spinous rays ; the three posterior are 

 exceedingly small, and look like isolated spines, between the fins. 



The second dorsal is one third longer than high ; its rays are bifid, and their tips 

 slightly project beyond the connecting membrane. 



The pectorals are very broad when expanded, and are one third the length of 

 the body. On a line with the base of the pectorals, beneath them, are three fleshy 

 appendages, somewhat similar in their appearance to the fin rays, though larger, and 

 of equal size throughout their entire length ; the upper, which is the longest, is equal 

 to half the length of the pectorals. 



The ventrals are situated beneath the base of the pectorals ; their longest rays 

 are equal to two thirds the length of the pectorals ; the connecting membrane is emar- 

 ginated between the tips of the rays. The first ray is spinous, and shorter than the 

 others. 



The anal fin arises back of, and terminates posteriorly to, the second dorsal, which 

 fin it equals in length. 



VOL. V. NEW SERIES. 10 



