EZ THE’ FISHES OF OHIO. 
ment of the lower pharyngeal teeth that constitutes the particular 
‘‘béte noire’’ of the uninitiated, but this must be mastered or 
many identifications will be impossible. The lower pharyngeal 
bones form the fifth pair of gill arches and usually bear teeth on 
their inner surfaces, and to examine these it is necessary to 
remove the bones. ‘This is most easily done in the case of the 
minnows and other small species by lifting the opercle and insert- 
ing a small hook behind the gills. In the sunfish and suckers 
and other larger forms it is best to run a scalpel around them 
before attempting to remove them. The teeth when removed are 
usually covered, more or less, with broken tissues, which can be 
removed by cleaning carefully witha fine-pointed needle, or with 
a soft brush under water. Incase the teeth have been broken 
off, as frequently happens, the bases can be distinguished. A 
good hand lens is essential. In native minnows the pharyngeal 
teeth are in one or two rows, and their number and arrangement 
is expressed by a formula—thus 1,4-4, 2, meaning that on one 
side the small, inner row consists of one tooth, and on the oppo- 
site of two, while the teeth of the outer row are the same on both 
sides. ‘The fins are composed of stout spines, or soft rays or sf 
both. In the fin formula the number of spines is expressed by 
Roman characters, and the rays by the Arabic figures. Thus the 
formula, ‘‘D. X, 14,’’ indicates that the dorsal fin is composed of 
ten spines and fourteen rays. If the dorsal fin were in two parts 
the formula would read ‘‘D. X-rq4.’’ In counting the number 
of rays the undeveloped rudimentary ones are not usually consid- 
ered except in the case of the catfish. A little allowance may be 
made for variation in number of rays. In small specimens where 
the rays are not always easy to count, a good way to determine 
the number is to draw the point of a pin forward over the fin 
near the base of the rays. A good lens is also useful. The 
dorsal fin is usually referred to in descriptions as simply the 
dorsal, and other fins in like manner. They are further abbrevi- 
ated by using D., A.,C., V. and P. to stand for dorsal, anal, caudal, 
ventral and pectoral fins respectively. The scalcs are counted 
along the lateral line (a longitudinal row of scales each with a 
small pore in most fishes) from behind the opercle to the base of 
the caudal fin, and the transverse rows are counted from the front. 
