424 CALIFORNIA ACADEMY OF SCIENCES. 52 



mens have been compared. The original specimens came 

 from a bottom of volcanic ashes. 



69. Chaenomugil proboscideus (Giinther). Lisita. 

 Very common in rocky places, reaching a length of 



about 6 inches ; not found by us in open water. 



70. Querimana harengus (Giinther). Verde. 



Very common in the bay and estuary; often seen swim- 

 ming in schools on the surface after the fashion of whirli- 

 gig beetles; occasionally taken in rock pools. Back 

 bright green, in life with a large, shining, silvery spot on 

 each side of the back. This spot becomes inconspicuous 

 when the fish is taken out of the water, but is a prominent 

 recognition mark while the fish is swimming. 



71. Agonostomus nasutus Giinther. Trucha. 

 Extremely abundant in the fresh waters of the Rio 



Presidio, especially in the swift places or ripples. It 

 reaches a length of over a foot, but most of the speci- 

 mens are much smaller. 



Head 4 to 4^; depth 4^ to 4^; dorsal IV-i, 8; 

 anal usually II, 10, very rarely II, 9; scales 43-13; maxil- 

 lary 3% to 3 T V; eye 3^ to 4^ ; snout 3% to 4; pectoral 

 i}i to 1% ; caudal equal to head. 



Body moderately elongate, not much compressed, nape 

 prominent, rounded. Interorbital much rounded, 3 in 

 head. Preorbital narrow, as wide as pupil. Mouth rather 

 small; maxillarv reaching front of pupil; lower jaw in- 

 cluded. Eye large without adipose eyelid. Teeth small, 

 in villiform bands. Gill-rakers slender, short, close set. 

 Pectoral short, not reaching first dorsal. Ventrals under 

 middle of its length, each with a small axillary scale. 

 Anal and soft dorsal with the free edge concave ; caudal 

 well forked. First spine of anal very short, almost ru- 



