FISH FAUNA OF LAKES OF SOUTHEASTERN OREGON. 79 
SYSTEMATIC DISCUSSION. 
EXPLANATION OF MEASUREMENTS. 
It is intended that the tables of measurements given in this paper, besides 
being of use in the identification of the species under consideration, shall express 
the amount and character of the variation in certain details of structure as well as 
these can be determined by the study of a small series of specimens. It is pre- 
sumed that the true relationships of the forms will be more clearly and definitely 
A 
Fig. 1.—Diagram showing method of taking proportional measurements. 
Length of body (a) recorded in millimeters. Length head (b) measured from tip of snout to posterior edge of opercle, 
the opercular flap, which is likely to shrink, not being considered. Depth head, measured at occiput. Depth body, the great- 
est depth. Snout to dorsal (c), snout to ventral (d), tip of snout to anterior end of base of fin. Depth caudal peduncle (e) 
measured at the narrowest place. Length of caudal peduncle ( f), base of posterior anal ray to end of last vertebra; not to 
base of lowermost caudal ray, as the latter point is often indefinite. Length snout (g), tip of snout to anterior border 
ofeye. Diameter eye, varies greatly with age. In poorly preserved specimens the tissue surrounding the eye is cften 
shrunken, leaving the opening abnormally large. Only well-preserved examples nearly equal in size ought to be compared. 
Interorbital width, measured on skull, the points of the dividers being closed as nearly as possible between the eyes. Snout 
to occiput (h), tip of snout to the point on occiput where scales of body first appear. Length base of dorsal (i), length base 
of anal, from base of anterior to base of posterior ray, the extent of the membrane posteriorly not being taken into account. 
Height dorsal, height anal (k), length pectoral, length ventral (1), the length of longest ray in fin. Length caudal (m), meas- 
ured from end of last vertebra to tip of uppercaudal lobe. Scales lateral line, counted to end of last vertebra; not on base 
of caudal, where they frequently become densely crowded and difficult to make out. Scales above lateral line (n), from 
lateral line upward and forward to a point about midway between occiput and insertion of dorsal; not between lateral line 
and base of dorsal, as in the latter region the scales are sometimes minute, densely crowded, and indistinet. Scales below 
lateral line (0), from upper edge of base of ventral upward and forward to the lateral line. The series in the lateral line is 
not enumerated in this or the previous count. Scales before dorsal, the number of rows or series between occiput and base 
of dorsal. Dorsal rays, anai rays, when the posterior ray is cleft to the base it is still counted asa single ray. The anterior 
ray is often simple and preceded by one or two short, spine-like rays closely united toit. The spine-like rays are not 
enumerated. 
