486 CALIFORNIA ACADEMY OF SCIENCES. I14 
and five bronze bands more oblique than those on dorsal 
and hence not continuous the whole length of fin; caudal 
peduncle black, a whitish yellow cross-band behind spine, 
faint in adult, the anterior margin vertical, the posterior 
concave; rest of caudal black. Pectoral yellowish; ven- 
trals dusky, the spine black. 
Adult with the pectoral quite yellow: pale band at base 
of caudal growing faint with age: a blue streak along 
base ot dorsal. 
Numerous specimens, the largest about six inches in 
length, numbered 2899, in the L. S. Jr. Univ. Mus. 
187. Xesurus punctatus (Gill). Cocuiniro. Plate 
xlvi. 
Young specimens very abundant in rock pools about 
Mazatlan, hitherto known only from Cape San Lucas. 
It was not found by Dr. Gilbert at Mazatlan. Most of 
our specimens were secured by the use of the fish poison 
called gervo. By pouring this liquid into the rock ‘pools 
at low tide this and several other species were obtained 
in numbers. This gervo or gerbo is the milky juice of a 
tree called ava, abundant in the forests about Mazatlan, 
and apparently allied to the S¢trychnos nux-vomica. In 
rock pools no specimens exceeding two inches in length 
were found. Several very large specimens were obtained 
with dynamite about the islands of Creston and Isla Blanca, 
where the species reaches a length of 16% inches. 
Description of adult: 
Head 4; depth 2; dorsal VII, 26; anal II, 23; snout 
1% in head; eye 5%; pectoral long as head: ventral 
144; caudal 1%; second dorsal spine 2. 
Body deep, compressed, covered with fine velvet. Cau- 
dal with three stout compressed blunt spines, with broad 
bases, the tips turned upward. Some specimens with no 
other spines; others with many spines, similar in form 
