108 CALIFORNIA ACADEMY OF SCIENCES [Proc. 4rH Ser. 
ters by which they could be recognized. As there is evidently 
but one species of Cereus on this island, it seems necessary to 
reduce them to one, C. galapagensis, which can be recognized 
by the following characters. Arborescent, often 8 or more 
meters in height; trunk cylindrical, 15-30 cm. in diameter ; 
stems diverging; articulations short, robust, obtusely rounded 
at the extremities, with deep indentations at the points of union 
of the articulations, 18-angled, costae prominent. Flowers 
chocolate brown with yellow stripes. Outer petals broadly 
spatulate cochleariform, 2.3 cm. long, 2 cm. broad at tip, mu- 
cronate, margins entire to denticulate; inner petals cuneate 
mucronate, 2.4 cm. long, 8 mm. broad, margins dentate. Stig- 
mas 11, fruit oval rounded, resembling a large prune, as de- 
scribed by Weber, |. c. A flower from a specimen of this 
species from Chatham Isl. shows considerable divergence from 
the above description in that the outer petals are narrowly spat- 
ulate, 3.1 cm. long, 8 mm. broad, abruptly acuminate, somewhat 
cochleariform; inner petals narrowly lanceolate, 3.2 cm. long, 5 
mm. broad, acuminate, margins irregularly dentate. Excellent 
photographs of this species were published by Agassiz (1), PI. 
XVI and XX, where specimens from both Charles and 
Chatham Ids. are shown. 
C. nesioticus K. Sch. in Rob. (1), 179.—Asrinepon Ist. : 
fairly abundant on old cinder beds along the south side of the 
island. No other vegetation occurs near where the specimens 
were taken, (no. 2092). ALBEMARLE IsL.: Black Bight, 
Snodgrass and Heller; Christopher Point, Snodgrass and 
Heller; Elizabeth Bay, Snodgrass and Heller. CHATHAM ISL.: 
Sappho Cove, reported by E. S. King, one of the members of 
the expedition. JAmes Is_.: James Bay, common on recent 
lava south of the bay and along the south side of the island. 
NarporouGu Ist.: northeast side, common on recent lava (no. 
2093) ; south side, occurs to above 500 ft. acc. to J. S. Hunter. 
Tower Ist.: a few isolated bunches of this species were found 
on a small deposit of cinders around a blow-hole in the interior 
of the island (no. 2094). 
This species is always found in the most sterile and desert 
situations and never occurs where there is much if any other 
vegetation. On both Narborough and James Islands it was 
found growing abundantly on beds of lava apparently as fresh 
