56 
BULI.ETIN OF' THE BUREAU OF FISHERIES. 
SYSTEMATIC DISCUSSION OF SPECIES. 
Entosphenus tridentatus (Gairdner). Three-toothed lamprey. 
Lampreys have been taken in the San Lorenzo, Pajaro, and Salinas Rivers. They appear in 
large numbers in the San Lorenzo during the month of March. Young examples may be found during 
the summer (May-July) burrowing like earthworms in the soil of the river banks below the water line. 
A dead adult specimen was found in Nacimiento Creek July i6. 
Catostomus mniotiltus, new species. Pajaro sucker. 
This form, a representative of Catostomus occidentalis, the coarse-scaled sucker of the Sacramento 
system, differs from the parent species principally in having larger scales in the anterior dorsal region 
of the body. This difference, visible on a careful comparison of specimens from both river systems, is 
well illustrated by enumerating the series of scales between the occiput and dorsal fin and also between 
the lateral line and middle of back. 
10 
11 
12 
13 
14 
IS 
16 
17 
II 
6 
24 
36 
25 
S 
13 
66 
31 
Scales before dorsal 
23 
24 
25 
26 
27 
28 
29 
30 
31 
32 
33 
34 
35 
36 
37 
3 
16 
II 
7 
12 
I 
23 
15 
10 
12 
13 
I 
2 
6 
16 
18 
27 
23 
The mouth is smaller and the lips narrower in C. mniotiltus, and the body appears to be more robust 
and stalky. 
This species is not closely related to C. microps Rutter, of the Sacramento, the relationships of the 
latter being with the fine-scaled suckers C. rimiculus of the Klamath and C. catostomus of the Columbia. 
Description of the type, no. 74465, United States National Museum, from Arroyo Seco Creek, Mon- 
terey County, Cal. Length, 208 millimeters. 
Head 4.8 in length to base of caudal; depth 4.8; depth caudal peduncle 2.6 in head; eye 6; inter- 
orbital space 2.3; snout 2; dorsal rays 12; anal rays 7; scales in lateral line 57: between lateral line and 
middle of back ii; between lateral line and insertion of ventral 8; between occiput and insertion of 
dorsal fin 27. 
The head is short and broad, the body deep and stocky; interorbital area very convex; width of 
mouth contained 5 times in head; upper lip with about 5 rows of papillae; cleft of lower lip so deep that 
not more than i row of papillae lies between it and the border of mouth ; inner border of lips smooth and 
somewhat homy; about 4 rows of minute papillae between valve and upper border of mouth. Length 
of fontanelle equal to diameter of orbit. Origin of dorsal midway between tip of snout and base of 
caudal; highest rays 1.5 in head, not nearly reaching tips of last rays in depressed fin. Ventrals inserted 
beneath middle of dorsal, their length 1.7 in head, the edges rounded. Anal 1.5 in head. Caudal lobes 
slightly shorter than head. Pectorals rather obtusely pointed, 1.4 in head. 
Scales large and regular. Lateral line almost straight excepting a short curve immediately behind 
upper edge of gill opening. A row of mucous pores passes from near tip of snout, beneath and behind 
eye, then curves upward and turns backward to join the lateral line at upper edge of gill opening, from 
where it is connected with the opposite side of head by a similar row of p>ores across the occiput; another 
row of pores extends from occipital row forward above eye and near edge of nostril to near tip of snout. 
Color in spirits, dark on the upper surfaces, growing lighter below the lateral line; the ventral area 
white. Scales of the dark areas with dusky basal spots and narrow dark margins. Dorsal, caudal, 
and pectorals suffused with dusky color; ventrals and anal immaculate. In life the upper parts are 
dark olive, the sides with brassy and silvery reflections. Young individuals have a dark spot on the 
