FISHES OF STREAMS TRIBUTARY TO MONTEREY BAY. 
71 
Gasterosteus cataphractus (Pallas). Stickleback. 
Sticklebacks appear in all the streams tributary to Monterey Bay. They usually have from 4 to 
6 lateral plates, the sides being mostly naked and the caudal keel absent. Many fully plated examples 
were collected, hqwever, these being found near the mouths of the rivers in close proximity to salt water. 
An examination of the sticklebacks of this coast will scarcely bear out the conclusions of Mr. C. 
Tate Regan published in a recent paper.® He finds that a circumpolar species G. aculeatus extends 
downward along our coast to the Santa Clara River, Cal., and then gives place to G. santa-annae , a 
species inhabiting the Santa Ana River, which reaches the ocean a few miles to the southward of the 
Santa Clara River. The distinctive characters assigned to G. santa-annae are (compared with G. acu- 
leatus) sides of body without bony plates (rarely with 2 or 3 anteriorly); dorsal rays 10 or ii; anal rays 
6 or 7 (8); origin of first dorsal spine well behind base of pectoral and only slightly in advance of base of 
pelvics, 29 vertebrae. 
Some time ago Rutter b showed that in the region between the Santa Ana River and San Francisco 
Bay all conditions of lateral armature from entirely naked to completely plated sides might be found. 
Rutter’s notes show that of iii specimens from the Santa Ana River at Riverside, 104 were naked, 4 
had I plate, and 3 had 2 plates. Of 298 individuals from the Santa Clara River, 76 had no lateral plates, 
41 had I, 99 had 2, 67 had 3, and 15 had 4. These data seem sufficient to prevent differentiating the 
Santa Ana fishes on the character of lateral armature, and a perusal of Rutter’s paper will demonstrate 
the futility of attempting to show that the sticklebacks of any locality on this coast may be distinguished 
by the number of plates on the sides of their bodies. The present writer® examined about 2,000 
specimens taken in the rivers between San Francisco Bay and the Columbia, and became convinced 
that within, that region at least but one form could be recognized. The data at hand simply show that 
a larger proportion of naked examples have been collected in the Santa Ana River, but judging from 
what is known of the lateral armature of sticklebacks in other streams it would not be very hazardous 
to predict that further collecting in the Santa Ana would result in securing specimens that are more 
fully armed. That the Santa Ana fishes are not distinguished by peculiar fin structure is shown in an 
examination of 20 specimens selected at random from a collection from Santa Clara River, where 3 
examples have 10, 13 have ii, and 4 have 12 dorsal rays; 5 have 7, ii have 8, and 4 have 9 anal rays. 
The position of the first dorsal spine and also the number of vertebrae are likewise variable. In brief, 
no one seems able to find any characters or set of characters that will serve to differentiate the Santa Ana 
sticklebacks, or in fact those from any other river basin along the west coast. Perhaps it may be said 
that individuals of the species generally attain a larger size and a more complete armature in the north, 
while they are usually smaller and more scantily armed in the south ; and also that while such a geographic 
variation obtains a similar one seems to appear which is coordinate with habitat, i. e., heavily plated 
individuals are more generally found in or near salt water, while the more nearly naked ones usually 
occur in the rivers at some distance from the ocean. 
It seems better to retain the name G. cataphractus for west American sticklebacks until sufficient 
evidence shows that it is not tenable. 
Archoplites interruptus (Girard). Sacramento perch. 
Small sunfish were collected in the Pajaro at Sargent and near the junction of the Pajaro and San 
Benito. This species has not been reported from Coyote Creek nor any of the smaller streams tributary 
to San Francisco Bay. 
Hysterocarpus traski Gibbons. Fresh-water viviparous perch. 
Frequently seen in the Pajaro and Salinas Rivers. Does not occur in the San Lorenzo. 
“Regan, C. Tate; The species of three-spiued sticklebacks. Annals and Magazine of Natural History, ser. 8, vol. iv, p. 435. 
*> Rutter. Cloudsley: Notes on fresh-water fishes of the Pacific slope of North America. Proceedings California Academy 
Sciences. 2d ser., vol. vi, p. 243-254. 
•^Snyder, J. O., op cit.. Bulletin Bureau Fisheries, vol. xxvn, 1907, p. 183. 
