FISHES OF STREAMS TRIBUTARY TO TOMALES BAY. 



379 



when the water was low and clear, the stream was carefully examined for a distance of 3 or 4 miles above 

 its mouth, and although minnows and trout were plentiful, no suckers were seen. Neither is the 

 species well represented in Papermill Creek, which has a considerably larger volume of water. Much 

 time was spent in carefully observing the stream above Tocaloma before any individuals were seen. 

 Specimens were later obtained only with great difficulty, as they were uncommonly shy, seeking shelter 

 under driftwood and overhanging banks, usually disappearing long before the trout or minnows were 

 disturbed. 



When compared with examples of the species from Russian River and the Sacramento Basin, a 

 slight degree of differentiation appears in the Papermill Creek specimens. The dorsal fin is a little 

 higher, the caudal seems to be somewhat longer, and the scales a little larger. In numerous specimens 

 from the Russian and Sacramento Rivers, between which no differences have been detected, the dorsal 

 measures 0.15 to 0.21 of the length, while the Papermill Creek specimens have a dorsal measuring 0.19 

 to 0.23. The caudal of Sacramento examples measures 0.21 to 0.27, that of Papermill Creek specimens 

 0.24 to 0.29. Sacramento individuals have 13 to 17 scales above the lateral line, while those from 

 Papermill Creek have 11 to 13. These measurements have been based on only 15 specimens from 

 Papermill Creek and are not sufficient in number to be of real value. It is of interest, however, that 

 the apparent differentiation of these specimens is in the direction of that exhibited by C. humboldtianus 

 of Bear, Eel, and Mad Rivers. 



Measurements of 10 specimens follow: 



Measurements of Ten Specimens of Catostomus Occidentaus. Papermill Creek. 



Length of body nun 



Length head 



Depth body 



Depth caudal pteduncle 



Length caudal peduncle 



Length snout ^ 



Diameter eye 



Interorbital width 



Depth head 



Snout to occiput 



Snout to dorsal 



Snout to ventral 



Length base of dorsal 



Length base of anal 



Height dorsal 



Height anal 



Length pectoral 



Length ventral 



Length caudal 



Dorsal rays 



Anal rays 



Scales lateral line 



Scales above lateral line 



Scales below lateral line 



Scales before dorsal 



19S 



138 



.09 



.165 



.04 

 . 10 

 .16 



■5S 

 ■ 17 

 .08 

 .19 

 .24 

 . 21 

 •175 

 .26 



13 



7 

 69 



.08; 



•I7S 



. II 



.04 



■09S 



.i6s 



. 20 



■495 



■56s 



•175 



.09 



. 20 



•27 



• 23 



.18 



.26 



13 

 8 



68 



12 

 9 



30 



.09 



• IS 



. 10 



.04 



. 10 



.165 



. 20 



•50 



•565 



.19 



.08 



•23 

 • 17 

 .28 



14 



8 



64 



o. 24 

 . 22 

 .09 

 .165 



.04 



. ID 

 •17 

 . 20 

 •51 



•57 

 .16 



■075 

 . 20 



■ 20 

 . 21 



■ 155 

 •25 



13 



7 



62 



13 



o. 24 



• 23 

 .oS 

 •17 

 . II 



• OS 

 . lo 

 .165 

 . 21 

 •52 



• 60 



• 19 

 .09 

 •23 



.09 



• IS 

 . II 

 .04 

 .09 



• 16 

 . 22 

 •49 

 •575 

 .19 

 .08 



•■75 

 .26 



63 



o. 23 



• 25 



.08 

 .16 



. II 



■ 035 



• 09 



• 17 



. 21 

 •50 



•57 

 .185 



• 075 

 . 20 



. 18 



•17 



.24 



o. 24 



• 25 

 .08 

 .16 



. II 



• 045 

 .09 



■ 17 



. 22 



■ 50 



■S8 



• 17 

 .08 

 . 21 



■ 19 

 . 20 



• 17 

 .26 



0.2s 



• 24 

 .09 

 . 16 

 . II 



■ °s 



.09S 

 •17 



. 21 



• SO 

 ■59 

 . 18 



■ 07 



7 



60 



Hesperoleucus venustus Snyder. San Francisco roach. 



Examples of this species resemble those of the Russian River in the trim, slender body, rather 

 pointed snout, slender caudal peduncle, and long fins. They have usually 9 dorsal and 8 anal rays, 

 the number counted in 167 specimens being as follows: 



